stuartmemo/qwerty-hancock — pull request #2 by Sidnicious (2012-09-27 01:19:15+00:00)
Title: Ignore auto-repeated key presses

If I hold down a key, the `keydown` event repeats and the note plays many times at once.

This works around the browser’s behavior by keeping track of which keys are down and only firing one callback per key until the key is released.