Draw optimizations

This release is mainly about improving program's painting and layout.

• (Significantly) Reworked of the rendering to speed things up, especially on high resolutions
  • If you were running < 60fps before, it should be noticeably closer to 60 now.
  • If you were getting choppy audio before, that should be less likely now. You may be able to reduce audio buffer length.
• Added a setting for drawing the editor area at a higher pixel zoom. This is mainly for having taller pinned unit rows, which should be especially useful for high DPI displays. (But maybe some also prefer the pixel aesthetic)
• Added a setting for changing the width of the left piano.
• Added support for building with CMake (thanks OPNA2608!)
• Adjusted the radio button and separator styling (thanks Ewan Green!)

Because a ton of the rendering was refactored, there might be a few visual glitches. They should be easy to fix though once reported.