Merge pull request #154 from bpluim/master

Added CKISubmission and CKIRubricAssessment support to CanvasKit
Parse enrollment state to CKIEnrollment
Merge pull request #155 from nlambson/master

Parse enrollment state to CKIEnrollment
updates to support viewing making comments on submissions

as well as submitting.
Merge pull request #156 from derrh/master

Viewing submissions for students
updated podspec for new version
Merge pull request #157 from derrh/master

updated podspec for new version
Minor changes to files and submissions.
Merge pull request #158 from bpluim/SubmissionComments

Minor changes to files and submissions.
updated podspec for new version
Added public property of rubricCriterion, and added mediaComment to ckisubmission when submission is a media comment.

Also added position data to CKIRubricCriterion for proper ordering.
Updated Podspec
Merge pull request #159 from bpluim/MediaCommentSubmissions

Media comment submissions