Fix boost::function instantiation with vcxx.
Fix boost::function instantiation with vcxx.

Without this change, the generated boost::function object is empty, and
a boost::exception("empty boost function") is sent when it is used.
The reason for this weird behavior is unclear at this point.

	* src/object/root-classes.cc: Prefix function name with '&' to
	  get its address.

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