Simple HP display implementation.
Add support for old beatmaps
Implement disable mouse buttons
Which should allow you to change the color palette in the future for skinning purposes.
I didn't move _every_ color here, but most of them. The ones I left behind are mostly just shades of gray. Closes #126
General fixes
Style dropdown to match osu!stable
Fix PreferUnicode changing when nothing to play.
Test case enhancement for key counter
Add ISSUE_TEMPLATE.md
Update README.md
Support old beatmaps
Remove unnecessary items from OptionsOverlay
check if dimLevel is null on exit player
Better vscode launch config
basic background dim
Don't async/await song selection since audio operations are now on a …