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)

scene/3d/lightmap_probe.cpp

@@ -0,0 +1,4 @@
+#include "lightmap_probe.h"
+
+LightmapProbe::LightmapProbe() {
+}