Merge pull request #12 from berg/master

Don't crash if errorID is null
Added ANKTokenLimits, including max_file_size and following as per appdotnet/api-spec#316
New build
Added a convenience method that checks if a file is uploadable (which right now is done by checking the file size and comparing it to the max file size).
Added support for the new image_info object that comes back as part of the File response now, as per appdotnet/api-spec#324.
Added ANKFile -isImage
Fixes #13 (infinite loop)
JSONKeyForLocalKey now always returns *something* if passed a non-nil value. (falls back to the local key if no JSON key is found)
Updated build (multiple crashes and problems have been fixed since last build)
Added another ANKFile creation convenience method for creating a file using a pre-populated ANKFile instance, a file URL (so that AFNetworking does the nifty multipart-streaming thing), and handler blocks. I think there are still more API holes here that I will need to work on.
Key inconsistency: when the server sends file objects, the id key is "id". When we push file objects into an annotation, the key becomes "file_id".
ANKAnnotation now has +oembedAnnotationForFile, which makes it WAY easier to create an annotation for an embedded image
Turns out you need to pass the format as oembed instead of URL -- I definitely need more API surrounding the oembed stuff.
Updated binary build (new cocoapods release coming soon)
ADNKit 1.1.2
Fixed spec
Added a new ANKFile convenience method: +fileWithFileAtURL. This creates an ANKFile set up with properties gathered from the file at the passed URL. The result of this is ready to go straight into a createFile call.

ANKClient's file creation methods are now a little more aware of the type parameter.
New binary release
Implemented the user blocking API (http://developers.app.net/docs/resources/user/blocking)
Implemented the channel muting API (http://developers.app.net/docs/resources/channel/muting)