Fix error in email validation

Fix so that email validation no longer accepts addresses such as "mal.formed@example...com" or "mal.formed.@example." The fix is to require at least one atext following a dot. 

From http://www.ietf.org/rfc/rfc2822.txt:
dot-atom-text   =       1*atext *("." 1*atext)
where "1*" means "at least 1"