title: Python regexp \n issue
body: <p>This searched ok:</p>
  
  <pre><code>&gt;&gt;&gt; re.search(r'(.*?)\r\n(.+?)\r\n', 'aaa\r\r\nbbb\r\n').groups()
  ('aaa\r', 'bbb')
  </code></pre>
  
  <p>But when I replace one of three <code>b</code> to <code>\n</code> it not searched:</p>
  
  <pre><code>&gt;&gt;&gt; re.search(r'(.*?)\r\n(.+?)\r\n', 'aaa\r\r\nb\nc\r\n').groups()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  AttributeError: 'NoneType' object has no attribute 'groups'
  </code></pre>
  
  <p>But I want to parse in second case:</p>
  
  <pre><code>('aaa\r', 'b\nc')
  </code></pre>