Update pillow to 2.6.1
Limit Upload File Sizes to GridFS.

This commit puts a limit on the size of files that
course staff can upload to MongoDB. The limit is
enforced on the frontend in javascript as well
as backend via the /upload endpoint.

The limit is hard-coded in cms/envs/common.py and
may be changed according to the user's custom
needs.

If the user tries to upload a file that's too
large, an error message will pop up, with a
customizable url that pointing the user to an
external page with an alternate upload procedure.
This url is specified im cms/envs/common.py.
If not set, this url will not be displayed.
round-off weight, min_count and drop_count values while returing grading policy
TNL-884
Merge pull request #6092 from edx/zub/bugfix/tnl-884-save-weight-in-gradingpolicy

round-off weight value while returing grading policy
MA-182 Fix Mobile Subtitles.
Merge pull request #6221 from edx/hotfix/MA-182

MA-182 Fix Mobile Subtitles.
Merge pull request #4276 from edx/db/update-pillow

Update pillow to 2.6.1
Merge pull request #6224 from edx/release

hotfix-2014-12-11
Merge pull request #5731 from Stanford-Online/ataki/upstream

Limit Upload File Sizes to GridFS
mattdrayer/server-api-merge: edX Solutions Team Contribution: Server API
Removed Unused APIs