Some more code cleanup in tutorials

Hi, some more :-)
I've done all examples down to 'I', hope they are ok, and haven't broken anything 
 
The two I had problems with where FormattedTextFieldDemo, FrameDemo2. I think they both have functions missing from scala-swing. What we could do is move them into a issue saying 'functions x needed' or if easier just create a separate pull request for them (assuming you can't get them working without 'peer.xx' etc) 
(even found some errors in the original java code :-) )