Crash when user command calls itself

Create a user command and call that same user command from there, and Opus will crash.

Should not occur very often, but I accidentally created a loop with these user commands and then it crashes.
DO already prevents you from using a script commands name for a user command, nice.

I'm not hunting bugs, it all happened while doing this: Command: ListerDoubleClick (adds qualifier evaluation)
Where I use a user and script command with nearly identical names.

Thanks, we'll try to add some protection against that in the future.