Update Parser files for new versions of bisonc++.

This patch simply implements what the man page, bisonc++(1), says:

     Note:  Parser-class header files (e.g., Parser.h) and parser-class
     internal header files (e.g., Parser.ih) generated with bisonc++
     <4.02.00 require
     two hand-modifications when using bisonc++ >= 4.02.00:

     In Parser.h, just below the declaration

         void print__();

     add:

         void exceptionHandler__(std::exception const &exc);

     In Parser.ih, assuming the name of the generated class is `Parser’, add the
     following member definition (if a namespace is used: within the namespace’s
     scope):

         inline void Parser::exceptionHandler__(std::exception const &exc)
         {
             throw;  // re-implement to handle exceptions thrown by actions
         }