Patch for graph to add deleting nodes

gistfile1.txt

diff -r old/lib/graph.rb new/lib/graph.rb
--- old/lib/graph.rb
+++ new/lib/graph.rb
@@ -371,6 +371,13 @@
   end
 
   ##
+  # Deletes a node from the graph
+  def delete_node node_name
+    nodes.delete(node_name)
+    nodes_order.delete(node_name)
+  end
+
+  ##
   # Outputs a graphviz graph.
 
   def to_s
@@ -583,7 +590,7 @@
       self
     end
 
-    alias :"<<" :">>"
+#    alias :"<<" :">>"
 
     ##
     # Returns the edge between self and +dep_name+.
diff -r old/test/test_graph.rb new/test/test_graph.rb
--- old/test/test_graph.rb
+++ new/test/test_graph.rb
@@ -109,6 +109,22 @@
     assert_graph graph, 'label = "blah"', '"a" -> "b"'
   end
 
+  def test_delete_node
+    g = digraph do
+      node "a"
+      node "b"
+    end
+
+    assert_equal 2, g.nodes.length
+    assert_equal 2, g.nodes_order.length
+
+    g.delete_node("a")
+
+    assert_equal 1, g.nodes.length
+    assert_equal 1, g.nodes_order.length
+  end
+
+
   def test_label_html
     graph.label "<<B>blah</B>>"