Convert all email addresses to lower-case
Convert all email addresses to lower-case

Prevents duplicate accounts with identical e-mail addresses, and users
unable to log in if typing their e-mail address with the wrong case.

WARNING: This change is incompatible with existing databases containing
non-lowercase user e-mail addresses!

itsClay/node-auth,fix2015/BE-for-Gport,sp90/easy-node-authentication,jameelahuq/bankteller,istobarton/easy-node-authentication,scotch-io/easy-node-authentication,thenaughtychild/easy-node-authentication,ivanml/easy-node-authentication,fresh5447/working-passport,iblancasa/BackendSI2-IV,iblancasa/BackendSI2-IV,bessieatrazoyo/ScotchIOUserSocialLogins,niravshah/jobster,AlexGrosse/newbackend,bertdawg76/easy-node-authentication,BryanDuplantis/node-twitter-authentication,niravshah/jobster,daglipinank/easy-node-authentication,niravshah/seed,trizko/fileshareIC,zablon/BE-for-Gport,scotch-io/easy-node-authentication,gick/reveries-stable-servers,hansaliyad1/easy-node-authentication,AlexGrosse/newbackend,ellizzabbetth/easy-node-authentication,candiii-lin/dementia,didinnurdin/easy-node-authentication,nishanoire/bankteller,sanomi/easy-node-authentication,jameelahuq/authentication-demo,fix2015/BE-for-Gport,gick/reveries-stable-servers,joemaffei/neo4j-auth-test,joemaffei/neo4j-auth-test,wra216/CSE398-Project,jameelahuq/bankteller,gick/reveries-server,nishanoire/authentication-demo,seedor87/implementation_phase,morriswchris/easy-node-authentication,tegila/auth,nchlswtsn/easy-node-authentication,iblancasa/BackendSI2-IV,nishanoire/bankteller,fresh5447/working-passport,sejr/nodejs-fb-sample,Montana-Code-School/easy-node-authentication,zablon/BE-for-Gport,zablon/BE-for-Gport,Borgaard/easy-node-authentication,niravshah/jobster,wra216/CSE398-Project,tahoeRobbo/easy-node-authentication,ellizzabbetth/easy-node-authentication,niravshah/seed