1889: Don't show task limits if team doesn't use tasks
1894: Fix crediting where last sub is unsynced

* Often, the last subtitle won't be synced and will just extend until the end
  of the video.  In those cases, the "end" value is -1.  If that's the case, we
  can't add the credit sub.

* Made the add_credit() function dumber and easier to test (it now takes the
  list of subs, the language code and the video duration).  This makes it much
  easier to test.

* Rewrite tests (see above)
1890: Fix unittest logic
1980 Sync teamvideos linked to individual accounts
1866: Restore 'send message' button to user profiles
1865: Remove view counts sitewide
1966: Restyle disabled/assigned tasks
Merge branch 'production' into i-1890

Conflicts:
	apps/accountlinker/models.py
	apps/accountlinker/tests.py
1890: Fix check_authorization logic
1890: Fix unittests (yt imported versions)
1969: Add title attr for abbreviated video title links
1890: Fix more tests
2023: Sync to youtube when new version isn't made
2025: Sync to YT when marking lang complete in admin
Resolve merge conflicts betw prod and i-1866
Merge branch 'production' into i-1866
Merge branch 'production' into i-1890
Merge branch 'production' of github.com:pculture/unisubs into i-1865
1865: Remove view counts from subtitle view
Merge branch 'production' of github.com:pculture/unisubs into i-1889