set validity of used and unused tiles
Randomly generates and displays enemies
Randomly generates and displays potions
destructor of Board
weird indentation stuffs (silly vim)
movement and collision with enemies and potions
Randomly generates and displays gold and dragons
Merge branch 'dev' of https://github.com/gabybarsky/cc3k into dev

Conflicts:
	board.cc
player gold getter and setter
gold pickup and tile validation
remove unnecessary (duplicate) quantity field
gold malloc error fixes
Added comments
Added comments
Merge branch 'dev' of https://github.com/gabybarsky/cc3k into dev
optimize enemy spawning
Board documentation
Fixed to_string issue
optimizations
begin potion usage