more spanish translations

more spanish translations
Merge pull request #243 from cccaballero/master

more spanish translations
Merge pull request #244 from timrichardson/issue/1692

fix for Issue 1692 virtual fields in SQLFORM.grid
cleanup
virtual fields in SQLFORM.grid work with fields= grid argument
Merge branch 'issue/1692' of https://github.com/timrichardson/web2py into issue/1692