Merge pull request #17 from derrh/master

Adds model updating
Refactor all networking categories to be on CKClient

This was a bit more complicated than it sounds. It involved
getting rid of weird shared/current instances, changing the test
client a bit, etc., but ended up cleaning up everything. It also
meant getting rid of the CKILocalUser singleton instance and instead
making a readonly currentUser property on the CKIClient itself. Since
that was pretty much the only thin gin the CKILocalUser model besides
checking to see if we were logged in, I deleted the CKILocalUser and
got moved that method to the client as well.
Merge pull request #18 from derrh/master

adds path implementation for CKITab
Merge remote-tracking branch 'instructure/CanvasKit/master' into RACAttack

Conflicts:
	CanvasKit.xcodeproj/project.pbxproj
	Pods/ISO8601DateFormatter/ISO8601DateFormatter.m
Refactor OAuth and Example Project
Added CKITodoItem assignment property
test fix User.json
Merge pull request #1 from nlambson/master

Added CKITodoItem assignment property
Update README.md

updated for the CKIClient refactor
Stop trying to remove user from keychain twice.
Merge pull request #2 from jarsen/master

Stop trying to remove user from keychain twice.
Update CanvasKit.podspec
Update CanvasKit.podspec
Refactor keychain code and add access group
Fix keychain bug with current user.
Merge pull request #3 from jarsen/master

Refactor keychain code and add access group
Update CanvasKit.h with activity stream items
Merge pull request #4 from jarsen/master

Update CanvasKit.h with activity stream items
Update favorite courses endpoint.

Also moved it to the CKICourse category.