canvas resolution is configurable via slider

[chase-moskal]

the canvas could be displayed at different sizes.

we want to represent resolution in terms of a slider, from 10% to 100% -- the actual rendering resolution should be some percentage of the actual canvas dimensions

• let's say canvas is 1000x500 pixels in actual dimensions on the web page
• the resolution slider is at 50%
• the actual canvas rendering resolution should then be 500x250 (half the displayed width/height on the webpage)

[chase-moskal]

the current implementation seems to be backwards or something, when i lower it down to 10, it seems to render at high resolution, and the framerate gets worse

resolution at 10 should be very blurry and low-resolution

resolution at 100 should be crisp and render 1:1 for css screen pixels

we should allow higher resolutions than 100%, because high density screens can actually render "sub-pixel" densities

the slider should have a range from 10 to 200 (default is 100)