Acceleration for the bird.
Tileset and new files
Added modified javascript
Made the bird move better.
Saved everything
Added sounds and the bird can now eat worms.
Merge remote-tracking branch 'origin/master' into worldgen
worldgen: Remove some forgotten debug stuff.
worldgen: Initial terrain rendering tests.
worldgen: Fix some feature generation bugs. Add texture type to world data.
worldgen/textures: Tree and water drawing improvements.

Draw grass behind trees, draw trees with both textures, surround water
with the appropriate water hole grass textures.

Note: water can still generate too close to each other, which results
in incomplete water hole textures on some of the water holes.