New lightmapper

-Added LocalVector (needed it)
-Added stb_rect_pack (It's pretty cool, we could probably use it for other stuff too)
-Fixes and changes all around the place
-Added library for 128 bits fixed point (required for Delaunay3D)

core/math/plane.h

@@ -69,6 +69,7 @@ public:
 
 	Plane operator-() const { return Plane(-normal, -d); }
 	bool is_equal_approx(const Plane &p_plane) const;
+	bool is_equal_approx_any_side(const Plane &p_plane) const;
 
 	_FORCE_INLINE_ bool operator==(const Plane &p_plane) const;
 	_FORCE_INLINE_ bool operator!=(const Plane &p_plane) const;