codingstyle: trivial whitespace fixes

Reported by flake8.

backend: replace Pylons with TurboGears2

Replace the no-longer-supported Pylons application framework by TurboGears2
which is largely compatible/similar to Pylons.
Some interesting history is described at:
https://en.wikipedia.org/wiki/TurboGears

Changes by Dominik Ruf:
- fix sql config in test.ini

Changes by Thomas De Schampheleire:
- set-up of test suite
- tests: 'fix' repo archival test failure
Between Pylons and TurboGears2, there seems to be a small difference in the
headers sent for repository archive files, related to character encoding.
It is assumed that this difference is not important, and that the test
should just align with reality.
- remove need to import helpers/app_globals in lib
TurboGears2 by default expects helpers and app_globals to be available
in lib. For this reason kallithea/lib/__init__.py was originally changed
to include those files. However, this triggered several types of
circular import problems. If module A imported something from lib (e.g.
lib.annotate), and lib.helpers imported (possibly indirectly) module A,
then there was a circular import. Fix this by overruling the relevant
method of tg AppConfig, which is also hinted in the TurboGears2 code.
Hereby, the include of something from lib does not automatically import
helpers, greatly reducing the chances of circular import problems.
- make sure HTTP error '400' uses the custom error pages
TurboGears2 does not by default handle HTTP status code
'400 (Bad Request)' via the custom error page handling, causing a
standard non-styled error page.
- disable transaction manager
Kallithea currently handles its own transactions and does not need the
TurboGears2 transaction manager. However, TurboGears2 tries to enable it
by default and fails, throwing an error during application initialization.
The error itself seemed to be harmless for normal application functioning,
but was nevertheless confusing.
- add backlash as required dependency: backlash is meant as the WebError
replacement in TurboGears2 (originally WebError is part of Pylons). When
debug==true, it provides an interactive debugger in the browser. When
debug==false, backlash is necessary to show backtraces on the console.
- misc fixes

style: rename div.table to Bootstrap .panel-body

Based on work by Dominik Ruf.

tests: use test_context for tests needing internationalization

Instead of relying on the top-level handling of the translator, use the
newly introduced test_context.

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).

tests: add basic test for mark_all_read action of notifications

Adds test coverage for c7dc1c7ace67.

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: backout declassification of remove_all_notifications

In order to accomodate both nose/unittest and pytest at the same time,
method remove_all_notifications has been extracted from BaseTestCase in
commit 37d713674f63.
Now that nose/unittest is no longer used, we can backout this change again.

pytest migration: functional: switch to standard assert statements

Use unittest2pytest to replace unittest-style assert statements (e.g.
assertEqual) with standard Python assert statements to benefit from pytest's
improved reporting on assert failures.

The conversion by unittest2pytest was correct, except for line wrapping
problems.

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).

test_admin_notifications: fix index test dependency

The index test only worked because another test had prepared some database
state it relied on.

More specifically, the index test creates a notification
as a newly created user, but that user had not been committed to the
database yet. When running the index test standalone, this causes the error:

IntegrityError: (IntegrityError) NOT NULL constraint failed:
notifications.created_by u'INSERT INTO notifications (subject, body,
created_by, created_on, type) VALUES (?, ?, ?, ?, ?)'
(u'test_notification_1', u'notification_1', None, '2016-03-11
21:15:19.066402', u'message')

By committing the database after the user is created, the problem is solved.

tests: move remove_all_notifications outside of BaseTestCase

In preparation of allowing real pytest-style test cases (instead of
unittest-style ones), some reorganization is needed in the base test
classes, for one because we want a transition period where pytest and
unittest style test cases can live alongside each other, and secondly
because the pytest style test classes cannot have an __init__ method.

The BaseTestCase class will not be reused for the pytest test cases, but
the remove_all_notifications method will. To avoid having to duplicate it,
and since it does not use any resources from the class (self), move the
method out of the BaseTestCase class to top-level, and export it in
kallithea.tests.

tests: more consistently use unicode where unicode is expected

Nothing but extra u annotation to turn str constants into unicode.

This has been verified by hacking sqlalchemy to fail if wrong string types are passed.

security: apply CSRF check to all non-GET requests

The automatic CSRF protection was broken for POST requests with no
request payload parameters (but possibly containing request URI
parameters); a security hole was narrowly avoided because the code
base quite consistently checks the request method in the same way,
and because of browser protection against PUT/DELETE CSRF attacks.

Since explicit is better than implicit, the better way of checking
the HTTP request method is to simply check request.method, instead
of checking if request.POST is non-empty, which is subtly different
(it doesn't catch POST requests if all parameters are in the query
string) and non-obvious (because it also applies to PUT requests).

The commit also fixes some tests which relied on the CSRF protection
being broken. It does not fix all the controllers that still does
the misleading request.POST check, but since the CSRF check has now
been tightened, those are no longer a potential security issue.

cleanup: remove unused imports

Found with pyflakes.

notification tests: delete notifications before (not after) tests

Don't clean notifications (and changeset comments) *after* the test,
but *before* the test. Other unit tests don't care if they leave
notifications in the database, and neither should these. Rather,
they should ensure their *own* preconditions before testing.

Admittedly, currently only one test leaves a notification in the
database, but more could come along at any time (and why worry?):
TestPullrequestsController.test_create_with_existing_reviewer

notifications: use different strings for descriptions with age and datetime

Improves both English wording and makes it easier to translate correctly.

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