Changed fireball sound when hitting solid objects

Changed the fireball sound so that it plays Kick.wav when hitting enemies, and Bump.wav when hitting solid objects.
Restore end level fireworks

Fixes a couple of issues that were preventing the fireworks from appearing at the end of the level
Prevent jumping noises while going through pipe
Merge pull request #68 from dwilhelmi/master

Changed fireball sound when hitting solid objects, fixed fireworks, fixed jumping noises while going through pipe.
Platform-independent sounds

Both .mp3 and .ogg files are included, so all major browsers should be
able to play all audio.