Isolayer stuff should be in its own component

[matthewturk]

Right now the isolayer logic lives inside some of the base component code, and we should probably move it to a subcomponent. Possibly an isolayer component with a data reference to the block collection.

[chrishavlin]

agreed! i can't quite remember why it ended up there. i think there was a reason why it was more straightforward, but it'd be worth sorting that out and refactoring so that it is easy to separate out the logic.