Added greek translations.
Added George Venios as artist in credits.
Merge pull request #24 from veniosg/Greek_translations

Greek translations
Add content descriptions to PathBar image buttons.
Replace the useless 'item icon' content description with one based on the item type.
Correctly set content description on root image button.
Set the content description of PickBar's EditText to its hint. Also have the EditText request focus.