reduce nesting (evo.RequiresLevelUp is checked twice, only check once
and handle path)
compact some methods
seal some classes
add a little xmldoc to exposed members
fix b2w2 egg base levelup reference (not bw, b2w2!), doesn't really
matter much except for better indication (possibly?)
remove some unnecessary linq ToArray() calls
continue relocating code out of Core
Too many classes in the same file, break up.
simplify things a little in EncounterArea (remove passing thru nulls,
should throw excpetion immediately if misconfigured).
* Fix minlevel of Pangoro/Tyrantrum/Aurorus in gen6
30: level + dark type in the party
32: level + day
33: level + night
34: level + female
Note Meowstic isn't affected due to another entry of level + male (23)
* Minor text usage fix
* Fix xorPID flipping in TransferEC check
