fixup! Add a 'test drive' for the script interpreter
Default to 80 columns in the ScriptInterpreter prompt

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make the ScriptInterpreter prettier

While at it, output to a scroll pane (d'oh...).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>