Reorganized core/ directory, it was too fatty already

-Removed FuncRef, since Callable makes it obsolete
-Removed int_types.h as its obsolete in c++11+
-Changed color names code

core/math/a_star.cpp

@@ -31,7 +31,7 @@
 #include "a_star.h"
 
 #include "core/math/geometry_3d.h"
-#include "core/script_language.h"
+#include "core/object/script_language.h"
 #include "scene/scene_string_names.h"
 
 int AStar::get_available_point_id() const {