New calculator and measure tool

Possibly the largest update this plugin has seen yet.

• A new window called the mulch calculator shows up. The purpose is to not have to tab out of Quaver to do math.
  • It allows you to compute basic expressions, telling you the answer as you write it.
  • You can choose the level of precision, depending on how much floating point rounding you need.
  • You may also add additional calculators to store multiple numbers or expressions, up to 16 of them. I can very easily increase this amount, but I would need to see someone actually need it themselves.
• A new window called the mulch positions shows up when show note info is ticked. It functions similar to the amoguSV "Measure" tool. Unlike that tool, however...
  • ...it is able to tell distance with 100% accuracy by being completely game-accurate.
  • ...it has the added ability of being able to tell you absolute positioning instead of just being relative to the beginning selection.
  • ...it tells you information for every note selected, not just the beginning or end, and it includes long note tails.
  • ...it requires no CTRL+C to copy the number. Simply click the button, and it's now in your clipboard.
• Published to the Steam Workshop. If you want to receive automatic updates without cloning the repository, feel free to use that instead.