commit 54: add single level parent-child navigation for menus
commit 55: place menus on background container. add game container to background container instead of background container to game container
commit 56: set intro sequence. add skip feature.
commit 57: add audio controls
commit 58: build instructions screen
commit 59: prepare for submission
commit 60: use point object for mouse handler, use global importing on anonymous functions
commit 61: prevent stage events from firing during a button click in the game
commit 62: change energy increase/decrease methods to be part of the player rather than state controller
commit 62: improve audio button code
commit 63: tweak state controller
commit 64: comment code, make minor tweaks