title: Use ZIP-archives to store NSDocument data
body: <p>I noticed that Apple started using zip archives to replace document packages (folders appearing as a single file in Finder) in the iWork applications. I'm considering doing the same as I keep getting support emails related to my document packages getting corrupted when copying them to a windows fileserver.</p>
  
  <p>My questions is what would be the best way to do this in a NSDocument-based application?</p>
  
  <p>I guess the easiest way would be to create a directory file wrapper, create an archive of it and return it in NSDocument's </p>
  
  <pre><code>- (NSFileWrapper *)fileWrapperOfType:(NSString *)typeName error:(NSError **)outError
  </code></pre>
  
  <p>But I fail to understand how to create a zip archive of the NSFileWrapper.</p>