gitview: Use monospace font to draw the branch and tag name

This patch address the below:
Use monospace font to draw branch and tag name
set the font size to 13.
Make the graph column resizable. This helps to accommodate large tag names

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

contrib/gitview/gitview

@@ -160,9 +160,9 @@ class CellRendererGraph(gtk.GenericCellRenderer):
 		names_len = 0
 		if (len(names) != 0):
 			for item in names:
-				names_len += len(item)/3
+				names_len += len(item)
 
-		width = box_size * (cols + 1 + names_len )
+		width = box_size * (cols + 1 ) + names_len 
 		height = box_size
 
 		# FIXME I have no idea how to use cell_area properly
@@ -244,6 +244,8 @@ class CellRendererGraph(gtk.GenericCellRenderer):
 			for item in names:
 				name = name + item + " "
 
+			ctx.select_font_face("Monospace")
+			ctx.set_font_size(13)
 			ctx.text_path(name)
 
 		self.set_colour(ctx, colour, 0.0, 0.5)
@@ -515,8 +517,8 @@ class GitView:
 
 		cell = CellRendererGraph()
 		column = gtk.TreeViewColumn()
-		column.set_resizable(False)
-		column.pack_start(cell, expand=False)
+		column.set_resizable(True)
+		column.pack_start(cell, expand=True)
 		column.add_attribute(cell, "node", 1)
 		column.add_attribute(cell, "in-lines", 2)
 		column.add_attribute(cell, "out-lines", 3)