Use accept() directly in Nary.
Use accept() directly in Nary.

	* src/runner/interpreter.cc (visit(const ast::Nary*)): There is
	no need to go through "operator()" for exception handling as all
	the information is already present when dealing with the Nary
	components.

aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi