Update meters for member functions/variables changes
Move track info to a single rect object
Update for new rect tracking
Add method to retrieve slider value
Rework member variables / getters and setters
Slider logic
Make slider windows stay on top

These disappear once they lose focus anyway
Hide when we lose focus
Report the slider changes to the OSD

This allows us to push volume changes up the chain to the volume controller
Make dragging info visible

This lets us stop a volume change feedback loop
Add Show() method
Allow meter levels to be changed and remove test code