javax.swing.TextComponent getDocument to scala.swing.document.

peer.getDocument() replaced with document member function in scala.swing.TextComponent.
If you want to raise it in a bigger issue tracking system then there you can add it to issues.scala-lang.org and assign it to me. However given the code is in github I have a preference to trying to link up the issues and the code.

If you do have a go at this then you should remeber that you are trying to make this easy for a scala dev to use it, so there may not be a 1-to-1 mapping between java functions and scala-swing. 
As well as all the issues you mentioned we could add 'should addDocumentListener()' be more a stream/reactive system and not just a renaming wrapper to the existing code. Probably a lot of experimentation with different styles may be needed to come up with a good one