Fix for possibility of creating multiple accounts at once
Follow-up on @nicolaasmatthijs' review
Follow up on duplicate user creation
Follow-up on review for duplicate user issue
Rebased and deleted whitespace
Merge remote-tracking branch 'mathieu/duplicateuser' into duplicateuser
Follow up on multiple account creation and simplify the register widget
Merge pull request #3276 from bp323/duplicateuser

Possible to create multiple accounts at once