* generator/ObjectGen.cs : Add support for .custom files.
* gtk/Window.custom : clean up build
* sample/HelloWorld.cs : Use the customizations.
* sample/ButtonApp.cs : Use the customizations.
svn path=/trunk/gtk-sharp/; revision=4237
* codegen/defs-parse.pl (gen_object): Insert using statements. Insert
class members from corresponding .custom file.
* gtk/Window.custom : Renamed file from Window.cs. Removed all the
automatically generated members. This will be the mechanism used to
improve upon the mechanically generated binding.
svn path=/trunk/gtk-sharp/; revision=1282