Formatting system improved

`unveil<>` renamed to `fmt_unveil<>`, now packs args to u64 imitating va_args
`bijective...` removed, `cfg::enum_entry` now uses formatting system
`fmt_class_string<>` added, providing type-specific "%s" handler function
Added `fmt::append`, removed `fmt::narrow` (too obscure)
Utilities/cfmt.h: C-style format template function (WIP)
Minor formatting fixes and cleanup

Utilities/File.h

@@ -463,21 +463,3 @@ namespace fs
 	// Error code returned
 	extern thread_local error g_tls_error;
 }
-
-template<>
-struct unveil<fs::error>
-{
-	static inline const char* get(fs::error error)
-	{
-		switch (error)
-		{
-		case fs::error::ok: return "OK";
-
-		case fs::error::inval: return "Invalid arguments";
-		case fs::error::noent: return "Not found";
-		case fs::error::exist: return "Already exists";
-
-		default: throw error;
-		}
-	}
-};