Clarify the email validator error message
The existing error message is ambiguous as to what type of "address" should be typed in (e.g. web, email, mailing). This updates the error message to specify that the input failed validation because it wasn't an "email" address.
More info on the spelling of email : http://en.wikipedia.org/wiki/Email#Spelling
Merge pull request #1104 from gene1wood/clarify-email-validator-message

Clarify the email validator error message