Add the polish language
overwrite save() method on twinnable many many to use common ids instead of ids
assumed that key_to and key_from can not be arrays
Merge pull request #81 from vrcAlbert/delete_twinnable_many

overwrite save() method on twinnable many many to use common ids instead of ids
Merge pull request #79 from jiboule/feature/polski

Add some polish translations
Merge branch 'master/chiba2' into master/dubrovka