py3: remove safe_unicode in places where it no longer is needed because all strings (except bytes) already *are* unicode strings

(The remaining safe_unicode calls are still needed and can't just be removed,
generally because we in these cases still have to convert from bytes to unicode
strings.)

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

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

cleanup: get rid of most "import *"

Apply script generated with the following hack:
(
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(.*)' may be undefined, or defined from star imports.*/sed -ri 's,\\\\<\2\\\\>([^=]|$),XXXX.\2\\\\1,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.* undefined name '(.*)'$/sed -ri 's,\\\\<\2\\\\>([^=]|$),XXXX.\2\\\\1,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(from .*)\.([^.]*) import \*' used.*/sed -ri 's,\\\\<XXXX\\\\.,\3.,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(from .*)\.([^.]*) import \*' used.*/sed -ri 's,\2\\\\.\3 .*,\2 import \3,g' \1/gp" | sort -u
) | grep -v kallithea/bin/kallithea_cli_ishell.py > fix2.sh

journal: make "username:" filtering condition work as expected

As described in previous revision, using TEXT in JOURNAL_SCHEMA causes
unexpected results for "username:", too.

- tokenization by non-alphanumeric characters
- removing "stop words"

To make "username:" filtering condition work as expected, this
revision uses ID instead of TEST for "username" of JOURNAL_COLUMN.

journal: make "repository:" filtering condition work as expected (Issue #261)

Before this revision, journal filtering conditions like as below never
match against any entry, even if there are corresponded repositories.

- repository:foo/bar
- repository:foo-bar

Whoosh library, which is used to parse filtering condition, does:

- treat almost all non-alphanumeric characters as delimiter at
parsing condition
- join each conditions at filtering by "AND", by default

For example, filtering condition "repository:foo/bar" is translated as
"repository:foo AND repository:bar". This combined condition never
matches against any entry, because it is impossible that "repository"
field in DBMS table "user_logs" has both "foo" and "bar" values at
same time.

Using TEXT for "repository" of JOURNAL_SCHEMA causes this issue,
because TEXT assumes tokenization at parsing.

In addition to it, using TEXT also causes unintentional ignorance of
"stop words" in filtering conditions. For example, "this", "a", "you",
and so on are ignored at parsing, because these are too generic words
(from point of view of generic "text search").

To make "repository:" filtering condition work as expected, this
revision uses ID instead of TEST for "repository" of
JOURNAL_COLUMN. ID avoids both tokenization and removing "stop words".

This replacement should be safe with already existing DBMS instance,
because:

- JOURNAL_SCHEMA is used only to parse filtering condition
- DBMS table "user_logs" itself is defined by UserLog class
(in kallithea/model/db.py)

BTW, using ID also avoids normalization by lowercase-ing. But this
doesn't violate current case-insensitive search policy, because
LOWER-ing in actual SQL query is achieved by get_filterion() or so in
kallithea/controllers/admin/admin.py.

tests: introduce more test coverage of whoosh filtering

This has been extracted from other changesets by Mads Kiilerich to establish a
test baseline so we clearly can see what the following fixes are fixing.

Some of these tests will thus demonstrate bad behaviour - that will be fixed
later.

tests: add as little code as possible in __init__.py

kallithea/tests/__init__.py contained quite a lot of code, including the test
base class TestController. This in itself may be considered bad practice.

Specifically, this poses a problem when using pytest 3.0+, in which asserts
in some files are not automatically rewritten to give improved assert
output. That problem can be fixed by explicitly registering such files for
assertion rewriting, but that register call should be executed _before_ said
files are imported. I.e. if the register call is in
kallithea/tests/__init__.py, assert calls in __init__.py itself can not be
rewritten.

Since the TestController base class does effectively contain asserts, and we
do not want to execute the register call from somewhere outside the
kallithea/tests directory, we need to move the TestController class to
another file (kallithea/tests/base.py) so we can have a register call in
__init__.py before loading base.py.

While not strictly necessary to fix the mentioned pytest problem, we take
the opportunity to fully clean __init__.py and move everything to
the new kallithea/tests/base.py. While doing so, unnecessary imports are
removed, and imports are ordered alphabetically. Explicit imports of symbols
from modules that were already imported as a whole, are removed in favor of
fully qualifying the references (e.g. tempfile._RandomNameSequence).

cleanup: get rid of dn as shortcut for os.path.dirname

We keep 'dirname' as shortcut despite having removed the 'join' shortcut:
* the name is less ambiguous than 'join'.
* dirname is often applied multiple times - spelling it out would be too
verbose.

pytest migration: rename TestControllerPytest back to TestController

The name TestControllerPytest was introduced to allow a temporary situation
where nose/unittest and pytest-based tests could coexist.
This situation is now over, so the base test class can be renamed again.

pytest migration: convert functional tests with setup/teardown methods

pytest also supports setup/teardown methods like unittest (even though
pytest fixtures are more powerful and should be the end goal).
Only difference is the naming and signature of setUp (setup_method) and
tearDown (teardown_method).

remove vestiges of Python 2.5 support

We only support Python 2.6 and 2.7; hence we do not need to import
with-statement support from __future__.

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