Translation support for alerts/confirms/prompts

* Fix .po files (support for translation of notification/messages from controllers/*.js )
* Example translations to spanish
* Fix typos
* Fixes #1373 
* Fixes #1386
* Fixes #1417 

Note: To avoid making many changes in controllers and some *.js files, I created a dummy html file that includes all (or almost all) words for translating without make many modification in javascript files.