Fix touch events on android

[jameslindesay]

Tried on firefox and chrome, neither work.

I get a line drawn when I tap that I assume is a single pixel since the statistics show up as 550, 50, 28.87 (default uniform distribution).

[jameslindesay]

Probably the touchmove event because it knows the canvas is being touched.

[jameslindesay]

See https://stackoverflow.com/questions/20412982/javascript-any-workarounds-for-getting-chrome-for-android-to-fire-off-touchmove

And

https://stackoverflow.com/questions/11204460/the-touchmove-event-on-android-system-transformer-prime