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
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'
Merge pull request #81 from matthewrice345/master

Updates some gradle files
Updated the build tools version for gradle
Merge pull request #82 from matthewrice345/master

Updated the build tools version for gradle
Fixed Kaltura media uploading