Reverted an eye-node onto a parent coordinate system.
Changed atan to atan2 in matToEulerXYZ and matToEuler.

Return values are in the range [-pi,+pi] radian.
A node can be a light.

Space:setLight(light_node)
Space:setLightType(light_type) light_type = 0:point, 1:parallel
Space:getLightType()
Performance tuning.