Remove autoplay for video in course about page

The iframe was generated with autoplay=1, which, sometimes, would cause
the video to play in the background.
missed rst
add infinity symbol to calc preview
Add info for polls
Start documenting Staff Debug Info

STUD-1273
Display only the first component name in the page (and nav) title.
STUD-1351
Add error notification for XBlocks in Studio
Further updates to Polls
adding in gray versions of social icons for use in new email template. Using new name to ensure old links and existing emails using older templates still stay active
Move FieldDataCache assert to check both get and get_or_create
Merge pull request #2748 from edx/db/document-staff-debug-info

Start documenting Staff Debug Info
Fix typo
Merge pull request #2764 from edx/sylvia/documentation/BLD-672

Fix typo
Removing Vagrantfile, no longer used, please see configuration repo
Add JSdraw to INSTALLED_APPS if we can.
Add label to the checkboxes sample template.
Merge pull request #2757 from edx/will/studio-xblock-error-notification

Add error notification for XBlocks in Studio
Add polls and randomization to problem information
Update django-wiki revision
Merge pull request #2770 from edx/dcs/mat-4

Update django-wiki revision
fixes MAT-4