Fixed assignment operator on radian class
Added vector2 class
Removed cross product definitions
A bunch of work converting code to the new classes. Broke a bunch of stuff in the meantime, still working on fixing.
Finally, the minimap, duck visibility based on the player's FOV, turning... It all works.
Merge branch 'dillon'

Conflicts:
	duck.cpp
	game.cpp
	radian.cpp
	radian.h