Gen 6: Add Hidden Power Fairy support
With the blooming of gen 6 mods and the advent of gen 6, add support
for Fairy-type Hidden Power so it can be used in gen 6 or gen 5.5 mods.
hpTypes max at 15 on gen 2 calcs and gen 3+ calcs if the maxTypes var
is at 15, so adding Fairy-type to the types array is harmless.