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

modules/csg/csg.cpp

@@ -32,7 +32,7 @@
 
 #include "core/math/geometry_2d.h"
 #include "core/math/math_funcs.h"
-#include "core/sort_array.h"
+#include "core/templates/sort_array.h"
 
 // Static helper functions.