Add OCTCapabilities
Add a method for fetching a server's capabilities
Unit tests for +fetchCapabilities…
Use OCTClientErrorUnsupportedServer if /capabilities fails
Add an example of capability checking
Refactor to match the new API under /meta
Update README example
Merge pull request #1 from github/capabilities

Fetch authentication metadata for a server
Merge remote-tracking branch 'octokit/master'

Conflicts:
	OctoKit/OCTClient.m