Selecting the pan or send buttons should change what the track control knobs do

[jgcook935]

When you select the pan or send toggle buttons we should toggle some variables in the TrackHandler to make sure the knobs affect the correct parameters.

The location of the knob leds and status should update depending on which page we're currently on (pan or sends). This is the only way these knobs will actually be effective. When you switch a page, your knobs are already set the location they are in Bitwig instead of the previous page's location.

[jgcook935]

this works for pan/volume, but i still need to hook up the sends