Remove the "sanity-checks" from Madx.command?

`Madx.command` can not veto automatically executed commands from CALLed files. It only gets invoked for commands that the user has explicitly typed or were written in the program. IMO, it should be exactly the other way round: prevent automatically loaded commands, but allow the user to do anything (let the user try and the program fail, if it so will).

Therefore, I'd suggest to strip this feature.