GRIM: Clean up io_readfrom with suggestions from Coverity
GRIM: Initialize Mesh::_faces
EMI: Initialize SoundTrack::_soundType
GRIM: Delete Set::_states without foreach as it could cause problems
EMI: Use new instead of malloc in VimaTrack
EMI: Use correct name for kPlainSoundType
GRIM: Move Sprite into it's own file
EMI: Use a Sprite's costume in order to share materials