force lowercase for email/username

[knutole]

Currently email/username is case-dependent. So for example, it's not possible to log in with KNUTole@systemapic.com, because the checks are case-dependent.

This is unnecessary, and all usernames/emails should be converted to lowercase at all times.

• [x] .toLowerCase() when registering user (both email and username)
• [x] .toLowerCase() when checking for unique username/email
• [x] .toLowerCase() when searching for users on server (ie. every User.findOne() lookup)
• [x] add tests
• [ ] script to convert all existing user's usernames/emails to lowercase (@knutole)

[IgorZiegler]

Great stuff! will do it!

[IgorZiegler]

@knutole Can we close it?

[knutole]

@IgorZiegler I will close it when I write script.