Update to support optional email register and signin

lib/config.js

@@ -94,6 +94,7 @@ var google = (process.env.HMD_GOOGLE_CLIENTID && process.env.HMD_GOOGLE_CLIENTSE
     clientSecret: process.env.HMD_GOOGLE_CLIENTSECRET
 } : config.google || false;
 var imgur = process.env.HMD_IMGUR_CLIENTID || config.imgur || false;
+var email = process.env.HMD_EMAIL || config.email || false;
 
 function getserverurl() {
     var url = '';
@@ -151,6 +152,7 @@ module.exports = {
     dropbox: dropbox,
     google: google,
     imgur: imgur,
+    email: email,
     imageUploadType: imageUploadType,
     s3: s3,
     s3bucket: s3bucket