Update login_model.php

proposed change to fix facebook registration if the cleaned facebook username already exists...
the generateUniqueUserNameFromExistingUserName function should also be useful for clashes when twitter / google plus registration is added
Merge pull request #361 from atdotslashdot/patch-1

Update login_model.php
PSR / code style fixes for generateUniqueUserNameFromExistingUserName()
PSR / code style fixes for generateUniqueUserNameFromExistingUserName()
changes Feb 1st 2014
cleaning of input should be with strip_tags, not htmlentities() #341
changes Feb 1st 2014
Removed die()'s at parts where the header did not effect any code execution
Merge remote-tracking branch 'upstream/develop' into develop
Merge branch 'develop' into develop-phpunit