Add synchronous version of Verimail.verify

Hi,
I needed to plug in verimail into a validation framework that requires synchronous validation methods. To get this done I extracted the synchronous portion of verify() into verifySync() and refactored vefify() to use verifySync() internally.
As it stands they are basically the exact same method with a different interface, given that the portion of verify() that would actually need to run asynchronously is commented out.