Since I was making the renderer be able to adjust resolutions on the fly, I figured, why not also support high-DPI screens? (e.g. MacBooks and so on)

For now the feature is disabled by default (because on my laptop performance is godawful, and I assume other peoples' machines may be similar), but if you want to enable it, open up your userconf.lua and set the value highdpi = true.

At some point I really ought to make the options menu, huh?

Oh and I also fixed how I broke the spark particles' radius. I knew something looked wrong with it!

Also, the resolution scaling support added a little glitch that caused the roaming eyes' reflections to flash whenever the resolution changed. In fixing it I realized a problem that made me wonder how it ever even worked in the first place. (Or in actuality, made me realize WHY some bricks never seemed to reflect in them.) So anyway the roaming eyes' reflections are now correct-ish.