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/os/os.cpp

@@ -30,11 +30,11 @@
 
 #include "os.h"
 
+#include "core/config/project_settings.h"
 #include "core/input/input.h"
 #include "core/os/dir_access.h"
 #include "core/os/file_access.h"
 #include "core/os/midi_driver.h"
-#include "core/project_settings.h"
 #include "core/version_generated.gen.h"
 #include "servers/audio_server.h"