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/file_access.cpp

@@ -30,11 +30,11 @@
 
 #include "file_access.h"
 
+#include "core/config/project_settings.h"
 #include "core/crypto/crypto_core.h"
 #include "core/io/file_access_pack.h"
 #include "core/io/marshalls.h"
 #include "core/os/os.h"
-#include "core/project_settings.h"
 
 FileAccess::CreateFunc FileAccess::create_func[ACCESS_MAX] = { nullptr, nullptr };