scripts: drop isort --wrap-length 160 - it is broken with py3 and not really necessary

Under Python 3, isort 4.3.21 failed with
https://github.com/timothycrosley/isort/issues/741 on
kallithea/controllers/api/api.py :

Traceback (most recent call last):
File "data/env/bin/isort", line 10, in <module>
sys.exit(main())
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 379, in main
for sort_attempt in attempt_iterator:
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 377, in <genexpr>
attempt_iterator = (sort_imports(file_name, **arguments) for file_name in file_names)
File ".../env/lib64/python3.7/site-packages/isort/main.py", line 88, in sort_imports
result = SortImports(file_name, **arguments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 207, in __init__
self._add_formatted_imports()
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 606, in _add_formatted_imports
self._add_from_imports(from_modules, section, section_output, sort_ignore_case)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 526, in _add_from_imports
import_statement = self._multi_line_reformat(import_start, from_import_section, comments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 552, in _multi_line_reformat
dynamic_indent, indent, line_length, comments)
File ".../env/lib64/python3.7/site-packages/isort/isort.py", line 705, in _output_grid
if len(next_statement.split(self.line_separator)[-1]) + 1 > line_length:
TypeError: '>' not supported between instances of 'int' and 'str'

vcs: drop _fix_path

The reasoning in hg _fix_path is no longer correct.

We only need it for stripping the trailing '/' ... but we would rather be
explicit about that. (But it is also questionable if we actually want it at all
- we should just pass the right data and fail on wrong data.)

py3: trivial renaming of .iteritems() to .items()

A bit like "2to3 -f dict", but we don't want list().

vcs: drop GitChangeset.id

It seems to be like raw_id, except the odd feature that it sometimes would
return 'tip'.

vcs: fix get_file_annotate - consistently bind sha so it has the right value when executing

The Git implementation did *not* save the sha value in the lambda expression
for the "changeset lazy loader". Thus, if the generator had moved on and
assigned a different value to sha when the expression was executed, it would
use the "wrong" sha.

Fixed by doing as the Hg implementation: bind the sha value as value of a
default parameter when defining the lambda expression.

The Hg implementation did however also save the line - it is not used, and
there is no need for that.

vcs: drop the superfluous and leaky hgcompat "layer"

Explicit is better. And gives less pyflakes noise.

py3: add b'' annotations in some places where they will be needed later

Mostly entirely trivial adding of b prefix that is a ignored for py2 ... and
also a bit of related trivial reformatting/refactorings.

hg: bump minimum version to 5.1

We will soon move to Python 3 which only will support 5.1 or later.

Remove old hacks and tech debt.

Also avoids future warning:
DeprecationWarning: inspect.getargspec() is deprecated since Python 3.0, use inspect.signature() or inspect.getfullargspec()

cleanup: minor refactorings and simplification of dict usage

Makes it more py3 compatible.

py3: cleanup map usage and avoid py3 ambiguity

Based on 2to3 -f map ... but replace map with something more explicit (unless
born and raised in a lisp world) (but sometimes slightly more verbose).

py3: use explicit octal literals

From 2to3 numliterals.

pylint: fix W0715(raising-format-tuple) Exception arguments suggest string formatting might be intended

kallithea/lib/utils2.py:453: W0715(raising-format-tuple) in get_changeset_safe: Exception arguments suggest string formatting might be intended
kallithea/lib/vcs/backends/git/changeset.py:360: W0715(raising-format-tuple) in GitChangeset.fill_archive: Exception arguments suggest string formatting might be intended
kallithea/lib/vcs/backends/hg/changeset.py:322: W0715(raising-format-tuple) in MercurialChangeset.fill_archive: Exception arguments suggest string formatting might be intended

hg: improve implementations of `successors` and `precursors` properties of Mercurial changesets

* On Mercurial versions supporting it, make the properties return the closest changesets in the obsolescence chain that are in the repository.
* On older Mercurial versions, fall back to the previous implementations.

hg: rename `precursors` variable to `predecessors`

This makes it consistent with the method name.

hg: rename `precursors` property of MercurialChangeset to `predecessors`

Mercurial changed the terminology around version 4.4.

hg: don't use custom diff arguments when generating diffstats for rss feed

With Mercurial 4.7, it is no longer possible to pass arguments like `git=True`
to `ctx.diff()`.

This will change the reported data slightly, but the difference isn't
important. Also, the code should be refactored to do something similar to what
we do in other places.

hg: support rename of obsolete related attributes in Mercurial 4.6

The internals and the UI should perhaps also change at some point.

hg: support annotate refactoring in Mercurial 4.6 for returning annotateline objeccts

Attempts at using annotateline.fctx will fail with AttributeError if we didn't
get an annotateline but an old tuple.

hg: refactor annotation to generate a list of normalized annotation lines before iterating

This makes it easier to add support for future annotion structures.

Temporarily add redundant conditional to preserve formatting and reduce churn.

hg: trivial refactorings of annotate functionality

Prepare for changes coming up.

hg: fix continuation binding of callback variables

The get_file_annotate generator yields a callback. That callback happened to
look at the current state of the generator. It happened to work anyway,
apparently because the callback always was called immediately, before the
generator state changed. But for example if the get_file_annotate was buffered
into a list, the callback would return the same result each time.

Instead, bind the generator iterator variables as named parameter values for
the callback function. That will make sure the callback always returns the
right value.

vcs: introduce 'branches' attribute on changesets, making it possible for Git to show multiple branches for a changeset

Mercurial changesets will always have have exactly one branch (which might be
"default"). The VCS data model was the same.

Git allows for a changeset to have 0 or more branches ... and possibly one of
them as active. The right data model is thus to have an enumerable of branches.

We thus add a 'branches' attribute and use it where applicable.

The existing 'branch' attribute used some heuristics to decide which branch use
as "the" branch ... and in some places code (and tests) rely on that. We thus
keep that old method, knowing that some of its uses probably should move to
'branches'.

The code for retrieving Git branches is based on work by Dominik Ruf.

vcs: add support for Mercurial annotate in Mercurial 4.4

Mercurial fctx.annotate() returns tuples with two elements: info about the
annotate line and the actual line. The code is changed to clarify that.

After Mercurial 4.4 with https://www.mercurial-scm.org/repo/hg/rev/2e32c6a31cc7 ,
the info is no longer a tuple but an attr object. Assume fctx is available as
an attribute, but catch exceptions and fall back to indexing as before.

That can't easily be done in hgcompat, so we do it inline.

codingstyle: replace "not ... in ..." with "... not in ..."

Reported by flake8.

codingstyle: trivial whitespace fixes

Reported by flake8.

hg: fix next() and prev() for obsolete changesets

If using evolve, the revision number is not longer the same as the (visible)
number of changesets.

When you clicked the next or prev button on the files page, simply nothing happened.

At the first click the files list got reloaded, but after that nothing happened.

annotate: invoke hg annotate in a way that is forward compatible with Mercurial 3.9

https://selenic.com/hg/rev/576ff900fcc7 changed the behaviour when
linenumber=None.

linenumber=False has been tested to work with our oldest supported Mercurial
version.

cleanup: fixes of checking for None

Don't update repoinfo for all repos if an invalid repo is specified.

vcs: remove pointless stream reopening / seeking in hg fill_archive

test_archival started failing after 8e72e78a7d9e refactored the controller to
pass a stream created by fdopen.

The failure was in code that doesn't make any difference anyway - just kill it.

vcs: replace recursive implementation of prev&next with iterative

It was recursing over the repo and could give "maximum recursion depth
exceeded".

The implementation is still inefficient.

Second step in two-part process to rename directories.
This is the actual directory rename.