C++ wrappers for libgnomeui and libgnomecanvas

I started C++ wrappers for libgnomeui and libgnomecanvas for GNOME2 – libgnomeuimm and libgnomecanvasmm. The
shouldn’t take long as we just need to update the stuff from
gnome– 1.2,x. However, I’m hoping that somebody will step
up to take over maintainership of at least libgnomecanvasmm.

I also put together a quick gtkmm_hello external example
to help the newbies.

All of this is in the gnomemm module in cvs, so people
should be able to get a good idea of the GNOME2 C++
situation by just glancing there.