Refactor iOS SDK to be more like Android

Still debugging this one.

Need to test Get file (pic) and delete pic.

For some reason even when the tests fail, they get marked as passed.

Debugging an ugly issue in Checkin/PATCH and DELETE where userAccessToken for some reason is always nil on the second chained request and so we send a device token and get a failure. I have no idea why this happens.

Just an FYI, the leading "/" is optional (and usually preferred that it is omitted for style).