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

servers/rendering/rasterizer_rd/rasterizer_canvas_rd.cpp

@@ -29,8 +29,8 @@
 /*************************************************************************/
 
 #include "rasterizer_canvas_rd.h"
+#include "core/config/project_settings.h"
 #include "core/math/math_funcs.h"
-#include "core/project_settings.h"
 #include "rasterizer_rd.h"
 
 void RasterizerCanvasRD::_update_transform_2d_to_mat4(const Transform2D &p_transform, float *p_mat4) {