XAR Imported Event should pass XAR information (name, items to install, etc)

Right now the XARImportedEvent is passing null as the data of the event.

There's a comment in the class:

• <li>source: null (TODO: this event should take the name of the imported xar as a parameter, and listeners should be
• able to match on it. For the moment, I cannot figure out how to get the name of the imported xar from the Package
• plugin)</li>

Since importXARToWiki(InputStream) is a private method and since it's called by importXARToWiki(File), it's easy to pass the name of the XAR file and the list of items to import.