My Polish friend has translated the new game button's tool tip

I saved this file's encoding as UTF-8 (with BOM).
Replace references to google code with github
Fixes two readme files and the DebianPackage control file.
Merge pull request #227 from mrtnptrs/rgc
Merge pull request #192 from JASheppard/polishTranslation_newGameButt_TT

My Polish friend has translated the new game button's tool tip