Identify and fix memory leak

[lanceewing]

It appears that there is a memory leak somewhere. On multiple occasions, I have left the app running in a browser windows and come back later to find that it has crashed with a memory related issue. And now today, the same thing has happened with the Desktop version, i.e. I left the Java window running through most of the day and noticed later on that it had thrown an out of heap space error. Not good. But given that it is happening also in the Desktop version, I should be able to monitor this more easily and see where the leak is happening.

If it helps at all, when it happened today with the Desktop version, it was attempting to put pixels into the AGI screen, drawing some text, at the point that the out of memory issue happened. What is unusual though is that the app was actually on the home screen, so the interpreter itself shouldn't have been running, but even if it was, it should be able to run the interpreter, ideally forever, without falling over with a memory issue.