Simplified code, use `get_for_path()`

Conflicts:
	pootle/apps/pootle_translationproject/views.py
Retrieve common export view context in a reusable way

Conflicts:
	pootle/apps/pootle_translationproject/views.py
Cleanup: Remove unused import
pootle_translationproject: Fix a migration
pep8: silence new E265 for block comments

pep8 v1.5.0 introduces E265 block comment should start with '# '.  Since
we blanked selected E26 we got E265 as soon as it landed.  We have too
many errors in Pootle related to this, mostly where code has been
commented out.  Some should be cleaned up but there is a conflict churn
issues that we'll hit with this.
signals: Fix unit_updated signal when there is no fuzzy unit
pootle_store: Add database cache columns for wordcounts and suggestion count
pootle_store/caching: Update total_wordcount on Unit.save()
pootle_store/caching: Update wordcounts when creating a new Unit
pootle_store/caching: Update Store caches when saving an existing unit
pootle_store: Get rid of calc_*_wordcount
commands: Update refresh_stats to actually refresh stats
pootle_store: Only calculate difference once
pootle_store: Do not calculate target_wordcount, ever

count_words is an expensive operation, and we don't really use
target_wordcount anywhere important.
Where it is actually used can be dropped in later commits.
pootle_store: Update suggestion_count on Suggestion updates
pootle_store: Get store suggestion counts directly from the db
commands: Refresh suggestion count in refresh_stats
pootle_store: Update the cache counts on Unit.delete()
pootle_store/caching: Get rid of old flag_for_deletion() calls
pootle_store: Move stringcount() to where it's locally used