Implemented Upcoming videos.

 - When uploading videos there are now two tabs allowing the user to
   choose whether the video already exists or is upcoming;

 - Upcoming videos now displayed on the front page;

 - Upcoming videos have their own display page.
Fixed some bugs regarding displaying upcoming videos.
Implement rollover on upcoming video thumbnails.

When mousing over an upcoming video thumbnail, the description of the
video appears. This only works when the thumbnail is a preview image.
Validate aspect ratio of the preview image.

When the user is uploading a preview image it has to have an aspect
ratio of 4:3.
Allow upcoming videos to be searched.
Implement user update of their own uploaded videos.

The video page will show an update link if the currently logged in
user has uploaded the video.
Update UI design.
Implement more UI improvements.

 - New icons for social login

 - New design for form submit buttons
More UI changes.
Revamp the contact and about pages.

Contact, FAQ, About DL and About EESTEC are all a part of the About
menu option.
Implement bug reports.

Added a new application: contacts. For now, there is only one model,
BugReport.
When a BugReport is created, an admin notification is also added.
More UI tweaks.