Refactored a lot of code from headers into impl headers only compiled into one TU

- also added noimpl option to single header script - which only generates the non impl code

projects/SelfTest/SurrogateCpps/catch_debugger.cpp

@@ -1,2 +1,2 @@
 // This file is only here to verify (to the extent possible) the self sufficiency of the header
-#include "catch_debugger.hpp"
+#include "catch_debugger.h"