This makes a few changes to bring things into a better shape during
mouse interactions with the mod panels:
- Dragging away from the panel now works in line with other buttons (ie.
`OsuButton`)
- Hovering now uses a lightened version of the current state, rather
than always using the active colour. I think this feels better.
- Mouse down now uses a transform point of 0.5. This is to give the
button a feeling of one of those latching light switches which resists
until reaching a point of overcoming the spring and switching state. I
think 0.4 (non-active) and 0.6 (from active) may work better, but left
at 0.5 for simplicity of implementation and I think it's good enough?
- Border always uses the gradiented version. I did this for simplicity
of implementation, but also think it looks better.
- Adjusted transform durations to feel better to me.
