3 months ago Polish translations were reverted to incorrect forms

Please undo the last commit of the file `lang/pl.php`

In Polish language in dates the name of the month must be in Genitive case.

Please refer to theseEnglish sources:
http://www.mediawiki.org/wiki/Template:I18n_month
http://stackoverflow.com/questions/17188316/month-name-in-genitive-polish-locale-with-joda-time-datetimeformatter

**Additional remark:**
Is it possibe to somehow lock the file against disrupting changes? This is the second time I need to manually downgrade your package to version which displays month names properly. Maybe we could put a remark in a comment inside of the file?