simon-game! shows squares and reads a sequence aloud.

Also responds to one- and two-finger swipes.
generates sequences, highlights, responds to gestures
upon tap, generate sequence, at finish call callback with sequence
Basic game flow. Still debugging.
Game can now actually be played, but needs usability tweaks

todo: vis/aud feedback during input
fix wrong highlight color bug

closures in hightlight function
block invalid gestures during sequence input

also don't stop upon tap during sequence input
and pause before starting game
pause between input and playback
title and gameover screens
Add scorekeeping to gameover and title screens.