A game for the Unofficial GBJam 2017 [https://itch.io/jam/unofficial-gbjam1]

An attempt to create a game without any graphics, apart from a simple start screen
with instructions.

The idea is to navigate a maze using a very simple echolocation system.

left/right to turn. step forward with up. A to tap but remain in place.
These three actions make noise. For each noise, we work out the distance to the next wall
in front, left and right of the player. We use this distance to generate a lag time
and volume for the return noise.

We have three sound probes, and three tone generators (we'll be using the custom wave
generator as a third square wave tone generator).
We map the two main tone generators to the left and right output channels,
and the custom generator to both (at reduced volume?).

Main game loop is greatly simplified due to not needing to base around vsync:
	poll for keypress
	react to keypress
	play noise
	calculate lags, assemble into list of what tones to play when
	sleep loop to each tone change point, until all tones have been played
	return to polling for keypresses