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
Rename "Flag" to "Method"; isn't used besides for indicating the evo
Method.
Remove some unnecessary duplicate checks
- always >=1 in chain at start
- mostEvolved already checked for > maxspeciesgen
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).
