Impaitent user commands should either override each other, or the user should be told to wait #151

If a shutdown command is pending, it will block other commands sent, like "stop." This is bad, because there are lots of times where a VM can't be shutdown with the shutdown command. So, if a user issues a more aggressive command, like stop, or reset, any pending commands for that VM should be cancelled, and then the new command should be issued. Or, a dialog should be raised to inform the user.

I vote for, and will implement, the former.