Partial pick: Add qualitychecks and translation stast ajax rendering (getting data via treeitem interface)

Pick notes: In the previous pick not all the changes were picked. Not sure if
    this is necessary, since we moved towards AJAX later.

Conflicts:
	pootle/apps/pootle_app/models/treeitem.py
	pootle/apps/pootle_misc/checks.py
	pootle/apps/pootle_misc/stats.py
	pootle/apps/pootle_store/models.py
	pootle/apps/pootle_translationproject/models.py
	pootle/apps/pootle_translationproject/views.py
	pootle/static/css/style.css
	pootle/static/js/stats.js
	pootle/templates/translation_projects/overview.html
Partial pick: Add translation actions ajax rendering, add critical column to main table view

Pick notes: Retrieved some changes that were left behind. Had to do a lot of
    adjustments because this code was already picked and further tweaked.

Conflicts:
	pootle/apps/pootle_app/models/treeitem.py
	pootle/apps/pootle_misc/checks.py
	pootle/apps/pootle_store/models.py
	pootle/apps/pootle_translationproject/views.py
	pootle/static/js/stats.js
	pootle/templates/translation_projects/overview.html