Added weapon and armor class. fixed polymorphism.

Turns out I was accidentally slicing the objects into an Item class
while picking up and dropping items. also made Item an abstract class.
Added function to load a map from file

moved the test map (a whole two squares) to gamemap.txt
mapformat.txt contains my ramblings on formatting gamemap.txt. Also
added a move function to the Coord class and updated Player::move to
utilize it.