Fixing issue where contents were displayed offset within the frame.

The entired contents of the window were occassionally being shifted out of the frame. Controls were responding as if the widgets were in their normal position. This was fairly reproducable by running more than one instace of TripleDemoJava at once.
Calling pack() before the JFrame is shown consistently fixes this. According to Oracle, pack() is meant to be called before setVisible(true) anyway. This has only been reported on OSX. This was fairly reproducable by running more than one instace of TripleDemoJava at once.