* NEW [POCKETVOX-GTK] improving modules managment

 - checking if two modules have the same ID before adding
 - checking if module has a valid ID before adding
 - adding a placeholder label in modules's entries
 - no more key, value set by the add_module callback
* NEW [POCKETVOX-GTK] adding placeholder for the listbox
* NEW [POCKETVOX-GTK] correcting bug when removing module
* NEW [POCKETVOX] translation and gui

 - Modifying the module's grid
 - adding a beginning of translatin for spanish user