Translation ca_ES for 245

A brand new Catalan translation for OJS 2.4.5.
* Initial clean translation was extended with the missing literals suggested by the "translation module".
* Newlines and header comments (including copyright) were unified (as much as possible).
* Copyright was extended with a Credit label linked to the OJS "ca_ES" translation page.

The translation is 90% complete as far as it includes:
* OJS core files (with pkp-lib submodule)
* Help files.
* Reading tools (General & Social science)
* Plugins (including new ones).
* Workflow graphics.

Only a few strings were keep in English (module "Object for review" and "Dataverse").

This translation was done using CAT sotware by the students of the Tradumatica master.

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A few extra notes about the translation:
* Desdoblament de gènere a la síl·laba tònica.
* Tractament de "vos" quan ens dirigim a l'usuari.
* Imperatiu per a les accions que ha de fer el sistema.
* Canvi del terme "connector" a "mòdul".