Koble - New background music & small chunks

On this update, the mayor feature is the new and incredible background music made by @SatiriMusic, with this, a button to play/pause the game sounds (On Safari you have to toggle to listen it) 

Other importan feature is the Chunk size reduction, from 100 to 64, this improves the performance of the game on web.

Bugs fixed:

• Removed debug button, but still works with (1) key.
• Removed fake walls on the chunk corners.
• Improved city generation, to prevent start on lava. (not completely solved)