License change: CC-BY 4.0
Add hurt2 sound from thecheeseman, CC-BY

http://freesound.org/people/thecheeseman/sounds/44429/
Add credits file
Add sound: hurt2 by thecheeseman from Freesound (license: CC-BY)

Converted to ogg from http://freesound.org/people/thecheeseman/sounds/44429/
Fix filenames
Update version to 2.2-dev