Rm todo am not going to do
Add JS to .gitignore
Add source map to .gitignore
Add draw-start-screen fn

* Shows "tap screen to start" message
Store played notes as on/off times w touch-id

* Only current note stored at the moment for each piano key.  But will allow note history in the future.
Rename draw to draw-instrument
Keywordize keys when unpacking touch events
Refactor control flow.

* One go block issues a start command when it is time to start updating instrument.  
* Instrument go block starts updating instrument and sending out latest instrument states on a channel.
* Draw go block listens on instrument state channel and draws instrument.