Merge pull request #46 from jarsen/master

Fixed the key for Web Conferences.
Add support for fetching single discussion with topic id
Merge pull request #47 from nlambson/master

Add support for fetching single discussion with topic id
Remove keychain from canvaskit

We really shouldn't be asserting opinions about the keychain
in our networking library. Clients can handle this on their own
if they want.
Merge remote-tracking branch 'instructure/CanvasKit/master'