title: (Kiss)XML xpath and default namespace
body: <p>I am working on an iPhone project that needs to parse some xml. The xml may or may not include a default namespace. I need to know how to parse the xml in case it uses a default namespace. As I need to both read an write xml, I'm leaning towards using KissXML, but I'm open for suggestions.</p>
  
  <p>This is my code:</p>
  
  <pre><code>NSString *content = [NSString stringWithContentsOfFile:[[NSBundle mainBundle]
      pathForResource:@"bookstore" ofType:@"xml"] encoding:NSUTF8StringEncoding error:nil];
  
  DDXMLDocument *theDocument = [[DDXMLDocument alloc] initWithXMLString:content options:0 error:nil];
  
  NSArray *results = [theDocument nodesForXPath:@"//book" error:nil];
  NSLog(@"%d", [results count]);
  </code></pre>
  
  <p>It works as expected on this xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;bookstore&gt;
  &lt;book category="COOKING"&gt;
    &lt;title lang="en"&gt;Everyday Italian&lt;/title&gt;
  &lt;/book&gt;
  &lt;book category="CHILDREN"&gt;
    &lt;title lang="en"&gt;Harry Potter&lt;/title&gt;
  &lt;/book&gt;
  &lt;/bookstore&gt;
  </code></pre>
  
  <p>But when the xml has a namespace, like this, it stops working:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;bookstore xmlns="[INSERT RANDOM NAMESPACE]"&gt;
  &lt;book category="COOKING"&gt;
    &lt;title lang="en"&gt;Everyday Italian&lt;/title&gt;
  &lt;/book&gt;
  &lt;book category="CHILDREN"&gt;
    &lt;title lang="en"&gt;Harry Potter&lt;/title&gt;
  &lt;/book&gt;
  &lt;/bookstore&gt;
  </code></pre>
  
  <p>Of course, I could just preprocess the string and remove the xmlns, though that feels like a sort of ugly hack. What is the proper way to handle this?</p>