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

include/internal/catch_list.hpp

@@ -11,6 +11,7 @@
 #include "catch_commandline.hpp"
 #include "catch_text.h"
 #include "catch_console_colour.hpp"
+#include "catch_interfaces_reporter.h"
 
 #include <limits>
 #include <algorithm>