Created NAVArrow
Created NAVSystem.
Implemented NAVSystem and NavArrow into game.
Cleanup, used new quad2triangles with alpha flag.
Bugfix: Ground units lacked big explosion (mushroom)
Bugfix: Silenced loud arithmetic exception for zero norm normalization.
Added HealthNotNeededException
Implemented HealthNotNeededException.
Added heading vector and rotation matrix to WorldObject2D
Bugfix: Exception chatter about zero-norm showstops
Used static final pad var instead of literal.
Bugfix: Boneheaded health overflow stuff again...