Boxwindow v2.1 update!

Boxwindow v2.1 has been released! It’s quite a small update:

1. Arrow keys support! Use arrows + Return + R. (Custom controls coming very very later)
2. Changed grey box’s physics, no more relying on “Separate two objects”. (for actual people, that means it's a lot more consistent)
3. Score text now uses Bitmap Text. I need to overhaul the menu, so the menu still uses the blurry default Text xd