Remove a check from prior work on Triples
Shifting is now a valid decision in Triples
Triples: implement autocenter
Support leaving empty slots when switching multiple mons in
This happens in Doubles or Triples if, in a single turn, more pokemon faint than can switch in.
This commit introduces two changes. Namely:
- If more pokemon faint in a single turn than can switch in, those with the higher positions now can have switch flags on.
- Passing a switch is now a valid decision that gets added to battle queue with maximum priority and disables the pokemon's switch flag.

As a side effect, this also allows running the battle engine in JS strict mode.
Make sure that moves restricted to adjacent targets have valid targets
Also Helping Hand's targetting is not hard-coded anymore.
Add Triples Custom Game format
Merge branch 'triples'