Fixed spanish translations in tr_es_ES.json. 

Also,I copied the fixed translations into the tr_es.json and tr_es_US.json files.

It seems that the are 3 files containing spanish translations *tr_es.json*, *tr_es_ES.json* and *tr_es_US.json*. tr_es.json is the one being used (at least in the chrome extension). The better translations were on tr_es_ES.json (the other ones were way off) so I fixed some mistakes in that file, added new terms to translate that were missing and then I copied it to the others two files.