gtk.ImageNewFromPixbuf and gdk gdk.PixbufNew binding
Fix provided by jrick: gdk.Pixbuf.GetPixels() now uses the reflect package to return a non-copied slice of Pixbuf data
Implemented gtk.GetPixbuf binding for GtkImage objects
Added reference and runtime finalizer to Pixbuf in gdk.Pixbuf.GetPixels() to avoid having the returned byte slice point to freed memory.
SetFinalizer needs an actual reference
Fixed runtime finalizer on gdk.Pixbuf.GetPixels()
Merge branch 'gdk-pixbuf' into vvanpo

Conflicts:
	gdk/gdk.go