Implemented email address validation

Interested in adding an email address validation?

I implemented a simple one, given the difficulty of writing an all-comprehensive email validation (see
http://stackoverflow.com/questions/624581/what-is-the-best-java-email-address-validation-method
http://davidcel.is/blog/2012/09/06/stop-validating-email-addresses-with-regex/ )

The proposed email validation checks the existence of one '@' and at least one point after the '@'