Merge pull request #76 from matthewrice345/master

Added some additional calls for the calendar event api
Adds onCallbackStart to APIStatusDelegate

Anything already implementing APIStatusDelegate needs to implement
the onCallbackStart() method
Merge pull request #77 from joshuadutton/master

Adds onCallbackStart to APIStatusDelegate
Added new file upload for user backdrop image.
Merge pull request #78 from Blackchai/master

Added new file upload for user backdrop image.
Upgrades retrofit so we can use OkHttp 2.0

OkHttp 2.0 fixes issues with authentication errors in retrofit,
plus it doesn't have problems interfering with other http clients
in 3rd party libraries like versions 1.* did.

This commit also fixes some logical errors in CanvasError and
updates to new Retrofit APIs.
Add default case to switch statement
Merge pull request #79 from joshuadutton/master

Upgrades retrofit so we can use OkHttp 2.0
Include permissions when getting courses.
Merge pull request #80 from bradylarson/master

Include permissions when getting courses.
Updates our gradle dependencies for Material Design
Merge remote-tracking branch 'upstream/master'