Refactoring some of the audio initialization code
Refactor
Audio handler now part of World object, and handling step sound effects via Keyboard::tick()
Merge branch 'master' of https://github.com/cookingclub/polarity into refactor-audio-hooks

Conflicts:
	world/world.hpp
Adding jump sounds, getting rid of old, crappy one
Merge branch 'master' of https://github.com/cookingclub/polarity into refactor-audio-hooks

Conflicts:
	physics/behavior.cpp