I replaced the transition parameter for nfaState, replacing it with a
single nfaState pointer. This is because any non-alternation state will
only have one next state, so the map was just added complexity.
I changed alternation processing - instead of having their own dedicated
fields, they just use the new 'next' parameter, and another one called
'splitState'.
I also changed the kleene state processing to remove the unecessary
empty state in the right-side alternation (it actually messed up my
matching).
