Release 1.20

Replace Crate Expectations with a new (simple) level, and add an eyedrop hint in the top-right of the UI.
Enable extra decorative sound effects. Fun :)
New zoom/scroll SFX.
New reset profile & 'invalid' SFX.
New 3D backgrounds for the last remaining two late-game areas.
Make histograms bouncy and add a dashed line for your previous stats.
Add a pointer to time controls after losing.
Fix colour flipping in held groups not adding to the undo history.
Fix flipping after rotating a held group.
Fix 'B.F.' description.