Wildcards first pass

- Wildcards only appear in Challenge Mode (they would break puzzles)
- Currently identified by quickly flashing between the 3 current palette
colors
- No more than 3 Wildcards on screen at once
- Every spawned card has 5% of being a Wildcard
- In a cube with 1 wildcard, if the 2 normal pieces have different
variants of a quality, that quality scores as All-Different. if the
normal pieces have the same variant of a quality, it scores as All-Same
- A cube with 2 or 3 wildcards scores as All-Same for every quality