[GREENFOOT-513] Investigate speed/memory issues
Several users (e.g. Dominic T, Matthias T) have reported issues with speed and/or running out of memory, which we should investigate -- this ticket is for taking an initial look for 3.0.2 to see if we can find any easy big wins (especially looking for big memory leaks), and then maybe later (>= 3.0.3) we should look for further small performance improvements.
- Issue type: Task
- Priority: Medium
- Fix versions: 3.0.3