core: Fix syntax errors on postgres
Pick 2.5.1.1 release notes
Fake staticpages initial migration only for 2.5.0

staticpages was added as legalpages in 2.5.0, so for older releases it
is necessary to run all the staticpages migrations, but for 2.5.0 the
initial migration needs to be faked.

This allows to directly upgrade without problems from releases older than
2.5.0.
Make setup command code sligthly more readable
Docs: Record upgrade fix in release notes
Docs: Update detailed upgrade instructions
Minor cleanups
Cleanup: Remove unnecessary CSS styles
Cleanup: Remove unused CSS
export: Always compare offset-aware datetimes

Thanks Toni Hermoso Pulido for reporting the issue

http://sourceforge.net/p/translate/mailman/message/32300565/
Cleanup: Remove unused TreeItem methods

Asked Taras about these methods and told that they are unused and that
were added for future potential optimisation that didn't happen.
tests: Initial tests for stats
tests: Unmark a valid test
suggestions: Only increase the count if the suggestion is new
tests: Add suggestion_count tests
tests: Add an accept_suggestion test
caching: Fix post-suggestion behaviour.