Move the camera considering the current orientation

Property definitions

gamnit $ EulerCamera :: move
	# Move the camera considering the current orientation
	fun move(dx, dy, dz: Float)
	do
		# +dz move forward
		position.x -= yaw.sin*dz
		position.z -= yaw.cos*dz

		# +dx strafe to the right
		position.x += yaw.cos*dx
		position.z -= yaw.sin*dx

		# +dz move towards the sky
		position.y += dy
	end
lib/gamnit/cameras.nit:86,2--99,4