.finally and subtrees

[paulyoung]

.finally should not be called on a subtree since the subtree is part of the parent decision tree. Calling .finally on the subtree would prevent further promise to be called.

I think we should make this error out if not already.

[bergie]

@paulyoung yeah, this will error since the parent node will subscribe to the subtree via a then, and doing that after finally throws.

Flowerflip/lib/Thenable.coffee

Line 9 in f6647fa

checkFinal: ->