Wrapping C Libraries with gmmproc

gtkmm uses the gmmproc tool to generate most of its source code, using .defs files that define the APIs of GObject-based libraries. So it's quite easy to create additional gtkmm-style wrappers of other glib/GObject-based libraries.

This involves a variety of tools, some of them crufty, but at least they work, and has been used successfully by several projects.