error_popup: show an error message window when simulator crashes

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@652 d9718cc8-9f43-0410-858b-315f434eb58c
toolstroke: fix bug in the bounds checking

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@653 d9718cc8-9f43-0410-858b-315f434eb58c