Features/849 email address

This cleans up the transmission of email and nickname to the submit.

I've also cleaned up the code by removing the AbstractCommunicator and started to pull out pure java code into org.mozilla.mozstumbler.service.core.*

All HTTP code is now in HttpUtil and is mockable behind the IHttpUtil interface.

Email addresses sent are hashed using SHA1 and encoded as a hexdigest.
check for null email and nick