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/MTProgressDialog.h

@@ -61,7 +61,7 @@ public:
 		Show();
 	}
 
-	force_inline void Update(const u8 thread_id, const u64 value, const wxString& msg)
+	void Update(const u8 thread_id, const u64 value, const wxString& msg)
 	{
 		if(thread_id > m_cores) return;