Sends all traffic to Player app.

Except for the admin app, all other traffic is now directed to the
Player app, since it will likely be the only app added to this project.
Adds Video and Activity models to player app.

Adds the most basic information necessary to add activities to a
video: an index of videos, and which webpages to show at which time
for that video.
Adds admin capability for Video and Activity models.

Video and Activity model data can now be edited in the default admin
interface. Also adds migration file for video and activity tables.
Adds "activites" view.

Adds view to get a JSON-encoded list of all activities for the
specified video. This data is requested by the player.js script to
know when to interrupt the video to load an activity page.
Fixes exception in activities view if video is not in the database.

Django's "get" method for models will throw an exception if the query
returns no or multiple results. Since each video view will query if
that video has associated activities, these exceptions need to be caught.
Adds activity data call to player.js.

Player JavaScript now calls the activities view for data on interactive
activities, and activates the Activity Manager if any are found. Also
now checks to see if there is an Activity Manager instance before
calling start and stop on it (after a playback change).