Added email checking support to the TNL login process.
Added email checking support to the TNL login process.

EduPepperPDTesting/pepper2013-testing,EduPepperPDTesting/pepper2013-testing,EduPepperPDTesting/pepper2013-testing,EduPepperPDTesting/pepper2013-testing,EduPepperPDTesting/pepper2013-testing,EduPepperPDTesting/pepper2013-testing