add attachments to submissions
add CKISubmissionSet to umbrella header
Add CKIMediaComment

and group all the comment stuff together in the project
add mediaComment to submission object
Add cookie for future update to canvas login
Merge pull request #86 from jarsen/master

Submission attachments and media comments
Merge pull request #87 from nlambson/master

Add cookie for future update to canvas login
Added ability to fetch sections for a course
Merge remote-tracking branch 'instructure/CanvasKit/master'

Conflicts:
	CanvasKit.xcodeproj/project.pbxproj