Fixed some format-string compiler warnings.
Added support for runloop-based delegate calls

If the delegate isn't running as an NSOperationQueue or dispatch queue,
but on a regular thread with a runloop (that _isn't_ the main thread),
there was no way to safely call the delegate. I added a new method
-setDelegateThread: that can be used for this: if set, the delegate
will be called via the runloop on that NSThread.
Don't send delegate -webSocketReadyForData: if not fully open yet.