Update login_model.php

Changes as described here : https://github.com/panique/php-login/issues/344
Merge pull request #357 from Yacine-krk/patch-1

Update login_model.php
changelog update
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
fixed #364 (Cookie deletion bug)
fixed #364 (Cookie deletion bug)
smtp link changed
Merge pull request #378 from panique/develop

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