* configure.in, src/Makefile.am, src/glade-paths.sh.in:
	  o Cleanup build in src/Makefile.am
	  o Now build and install a devhelp module if a usable version
	    of libdevhelp is available

	* src/glade-devhelp.[ch]: A loadable devhelp dockable widgets
	  built into a plugin module.

	* src/glade-app.c, src/glade.h: Added a global for glade_plugins_dir.

	* src/glade-project-window.c, src/glade-utils.[ch]: Detect if there
	  is a devhelp plugin installed and load the devhelp window into
	  the project window in a paned window with the project view.