* glib/Object.cs: make static GLib.Object.LookupGType protected for now. * gtk/CellRenderer.custom: code to allow for subclassing and
implementing a custom cell renderer.
* gtk/Makefile.am: add custom to build.
* gtk/glue/Makefile.am: add glue to build.
* gtk/glue/cellrenderer.c: glue code to override get_size and render
from cellrenderer.
* sample/CustomCellRenderer.cs: new sample to show how to implement a
custom cell renderer.
* sample/Makefile.am: add CustomCellRenderer sample.
svn path=/trunk/gtk-sharp/; revision=27426
