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/mbedtls/crypto_mbedtls.cpp

@@ -32,10 +32,10 @@
 
 #include "core/os/file_access.h"
 
-#include "core/engine.h"
+#include "core/config/engine.h"
+#include "core/config/project_settings.h"
 #include "core/io/certs_compressed.gen.h"
 #include "core/io/compression.h"
-#include "core/project_settings.h"
 
 #ifdef TOOLS_ENABLED
 #include "editor/editor_settings.h"