Move the remaining 'matching' methods to the Matcher class.
Clarify behaviour with a comment
Tweak the slot-state class manager to be a little more consistent
Name the handler for `change:is_possible`.
Move delayFromPosition to the only class that calls it.
Stop passing Settings all the way down to Slot models.
Remove an extra event trigger thats only important internally
Remove unused method.
Only one class triggers none_possible, need to listen to the matcher