Add synchronous version of Verimail.verify

[brpvieira]

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.

[typerandom]

Others have also requested a synchronous approach. To provide a clean API I will probably just make it so that if no callback is provided to verify(...), the call is treated as synchronous. However, if a callback is provided, it will be asynchronous. Ie. mixed verify(string test[, function callback]).