Have `Shiny.Random` be `0`, so we can skip init on this field for EncounterStatic. Plus makes it a little less brittle for future expansion if shiny qualities change.
Gen5 does not follow the same convention, 0 = non, 1 = rnd, 2 = always;
not gonna bother updating for just that one
bool? occupies 2 bytes; enum:byte is 1 byte.
should probably move validity checking logic into the IEncounterable
objects instead...
