Enhancement - T2 implementation

- Improved Att/Mod implementation.
- Implemented more T2 methods.

src/Att.h

@@ -44,6 +44,7 @@ public:
   bool parse (Nibbler&);
   bool validMod (const std::string&);
   bool evalMod (Att&);
+  bool match (const Att&);
   std::string composeF4 () const;
 
   void addMod (const std::string&);