Progress save
Changed gameboard_valid_moves so multiple initial positions can be specified.
- This allows for all possible moves a player can take to be generated in a single move
  and reduced as nessecery.
- Possible moves from a single tile are possible simply by bitwise and-ing the position of
  the piece in question and the positions of all the players pieces.
 On branch master
 Changes to be committed:
	modified:   bitboard.c
	modified:   main.c
 Changes not staged for commit:
	modified:   ai.c
	modified:   ai.h
First loose implementation of the ai_find_advantage function.
 On branch master
 Changes to be committed:
	modified:   ai.c
	modified:   ai.h
Added ai.c and ai.h to the build system
Added include directives
Added function to print out a players current advantage at the beginning of each turn.
Outlined the algorithm for generating the linked list of valid moves.