Implemented most of the backend portion of battlesys

note: doesnt compile due to null pointer exception that has to deal with
setting player's inventory

what battle system is missing:
+transition from curr map to world. have no idea how to do that without
screwing everything up. also forgot to backup my changes to player and
world so committing small changes until i remember what i implemented
for the two
+ ux/ui
+ some backend parts are unfinished since needs display class or are
dependent on user choice which is reliant on ux/ui. but once display &
user choice is integrated, finishing it up will be quick. unfinished
parts have detailed pseudo code on what needs to be done.