GUI unresponsive

[justin-ven]

The GUI becomes unresponsive during the build phase of a model run. After diagnosing a bit, it looks like the Event Dispatcher Thread (EDT) is occupied after the build button is pressed. This seems to be a basic Swing design problem. I have fooled about with SwingWorkers to try to fix this issue, but without success. This isn't too surprising as I have no previous experience with Java Gui design. Nevertheless, the issue would be useful to fix, as the code currently does not provide any user feedback even where the build phase is lengthy (the Output stream window should ideally provide some feedback via System.out statements).