Alias

- Implemented simple word substitution aliases. This is not the ultimate form
  which will involve the ability to insert arbitrary constructs.  Later.

src/Alias.h

@@ -39,7 +39,7 @@ public:
   void load ();
   void resolve (Tree*);
 
-private:
+public:
   std::map <std::string, std::string> _aliases;
 };