* configure.in : add test for System.Drawing. expand gtkdotnet.
* Makefile.am : add gtkdotnet.
* makefile.win32 : add gtkdotnet.
* gtkdotnet/* : new .Net extensions assembly. Moved the sample
sysdraw.cs Graphics class in here under the Gtk.DotNet namespace.
* sample/sysdraw.cs : moved to gtkdotnet/Graphics.cs.
* sample/drawing-sample.exe.config.in : killed.
* sample/DrawingSample.cs : use Gtk.DotNet.Graphics.
* sample/Makefile.am : make drawing-sample.exe build conditional
on gtk-dotnet presence.
svn path=/trunk/gtk-sharp/; revision=38745