Closes#2040 , adds test cases:
invalid bulbasaur.wc3: hidden ability
invalid charmander.pcd: hidden ability
valid camerupt: gen3->4 unevolved mismatch
valid leafeon: pcd mismatch -> evolved now matching
should be much easier to maintain; methods are reused with less overall
nesting
Checks.cs initially started out small, but over the years it has grown
to handle multiple types of checks. With all these checks next to
eachother, it's hard to see the overall groups. Splitting them up
(potentially further?) allows for more focused maintenance &
understanding.
Not sure if I'm happy with the overall bandaids used (checks no longer
done within LegalityAnalysis so variable repointing is excessively
used), but I'm happier the way it is now compared to the huge Checks.cs
