Make className part of the state of the dot.
Implement removing dots by completing a valid chain.

This is using a purely channel-based approach.
Add transition subscriber, but it isn't right.

Need to step away and do some thinking on the matter.
Try sending messages to channel in will-update.
Try using a separate chan for transitions.

This is a hopeful attempt at cleaning up the really weird issues with disappearing dots.
Add dot-column component.

The purpose of this is to have a useful parent class for a set of dots that must
change 'position' based on state changes in their siblings in the same column.
Add the react cljs package as dependency.
More work on trying to get the intercomponent comms right.
Change indentation on a cond for scannability.
Improve (Ithink) detection of whether we're mid-drag or not.
dot-column components now only subscribe to mouse events from their own dots.
Switch back to using mouse events for the chan.

Also, remove the 'chain-val' stuff since I have no idea when that will be ready.
Add missing recur call for a go-loop.
Remove the call to 'transition-chan' for now.
Add state to each column that keeps track of what color each dot on each row is.
Move transition sub from dot to dot-column.
Emit the transition message to the transition-chan again.
Make rows-map part of dot-column state.
Move transition subscriber to board-area.
Update om to 0.8.0-alpha1 to take advantage of ref-cursors.