Allocate space for the grid lines when they are enabled.

Allocate space for the grid lines when they are enabled.

2006-06-21  Kristian Rietveld  <kris@imendio.com>

	Allocate space for the grid lines when they are enabled.

	* gtk/gtktreeview.c (gtk_tree_view_bin_expose): make sure the cell
	area does not overlap with the grid lines, also draw the line for
	"the next cell" in the last loop iteration, make sure the cursor falls
	in between the grid lines,
	(validate_row): request extra space for the grid lines.