Jax now sets perspective according to actual canvas width
Jax now sets perspective according to actual canvas width

Previously, it used canvas.width and canvas.height, but these
represent framebuffer resolution, not necessarily the canvas
size itself. This led to strange bugs where the aspect ratio
was not quite right. Using clientWidth and clientHeight instead
fixes hits, because they represent the canvas's actual size in
the DOM.

sinisterchipmunk/jax,sinisterchipmunk/jax