title: Removing self-loops from undirected networkx graph
body: <p>I have created a graph from list of nodes using <code>networkx</code>. It has self loops. How to remove them? Following is sample:</p>
  
  <pre><code>import networkx as NX
  G=NX.Graph()
  G.add_edge(1,2)
  G.add_edge(1,1)
  print (G.edges())
  
  [(1, 2), (1, 1)]
  </code></pre>
  
  <p>I don't want <code>(1, 1)</code> edges.</p>