Improve terminology and share set chan

@flahertyb @barnabyc @ermanc @AdamEdgett @tlunter 

After a good brainstorming session yesterday we came up with a few changes. I think this is a much improved terminology. It now uses just 1 channel to update the state and the cursor which is a huge improvement.
yea indeed, the main cursor channel is what state trooper will output channels via to the outside world. This is how you get new cursors to send down through the component tree.