Added backend support for Comments.

- Single Vote per comment checks and balances added. 
 - Fixed up RsGxsImage stuff. (TODO move to proper REF counted Image).
 - Added GxsTokenQueue ticks were required.
 - Made GenExchange publicToken() fns  public, so that comments can use them.
 - Added OwnVote details to Comments 



git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@6224 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/gxs/rsgenexchange.h

@@ -362,6 +362,7 @@ protected:
         return ok;
     }
 
+public:
     /*!
      * Assigns a token value to passed integer
      * The status of the token can still be queried from request status feature
@@ -388,6 +389,7 @@ protected:
      */
     bool disposeOfPublicToken(const uint32_t &token);
 
+protected:
     /*!
      * This gives access to the data store which hold msgs and groups
      * for the service