Merge pull request #10 from derrh/master

Adds endpoints and model related to conversations
Merge pull request #11 from derrh/master

Implements path method for CKITodoItem
Merge pull request #12 from derrh/master

Uses the assignment id for the todo items path
Merge pull request #13 from derrh/master

I have fixed this bug at least 4 times
Add URL property to CKIActivityStreamItem
Add necessary url transformer to CKIActivityStreamItem
Merge pull request #14 from jarsen/master

Add URL property to CKIActivityStreamItem
Update README.md
Add class-specific IDs to stream items.
Merge pull request #15 from jarsen/master

Add class-specific IDs to stream items.
Fix ID properties in submission stream items.
Merge pull request #16 from jarsen/master

Fix ID properties in submission stream items.
Merge remote-tracking branch 'instructure/CanvasKit/ReactiveCocoa'