Closes#731
* Added catalan ca_ES language translation file
* Updated the catalan translation ca_ES.lang.php
Updated the catalan translation ca_ES.lang.php taking as reference difference with last version of english translation file.
* Quit sms_gateway labels not used on catalan
Removed about 10 translation labels with prefix sms_gateway_ on catalan translation file (ca_ES.lang.php) not used any more. I think that it really is the definitive good version ;-)
* Changed url
* Update ca_ES.lang.php
* Added Catalan to translations