New approach to combo manager.

My old approach has a problem where a user doesn't have
to enter the correct combo to pull it off. The old way
only checks that the proper buttons were hit in sequence.
If the user hits a wrong button somewhere in the middle
it would not matter.

That means most of the old code has to get ripped out.

The new approach is to spy on ig.input.bind/bindTouch
and keep track of streams of input. If the last n inputs
match any of the registered combos then the combo goes
off. Simpler, ultimately.
Removing combo starters and tracker concepts.

This fully breaks the class. Time to rebuild.
More testing, just starting the input stream test.
Tracking input stream.

Currently grows unboundedly. Have to make sure to
put a cap on that, probably relative to size of
largest combo or something.
COMBO!!!!