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/gdscript/gdscript_cache.cpp

@@ -31,7 +31,7 @@
 #include "gdscript_cache.h"
 
 #include "core/os/file_access.h"
-#include "core/vector.h"
+#include "core/templates/vector.h"
 #include "gdscript.h"
 #include "gdscript_analyzer.h"
 #include "gdscript_parser.h"