#54 No feedback if java is not installed

[Anonymous]

If java is not installed on a machine trying to run ROO (or is not properly installed as in: it's not available on the user's path), the user clicks on the run-script and only sees the prompt appear and disappear without being able to see any proper message as to why ROO is not starting.

This could be solved by making the script more complicated: try to detect java and if it's not available, then show a GUI message explaining the problem.