Provide over-ridable method calls before mutex locking in CommandableFragmentGenerator StopCmd and PauseCmd methods
In discussions with LArIAT folks, it's become clear that there are occasions where a CommandableFragmentGenerator child class may want to be alerted that a pause or stop request has been received before the mutex lock is attempted in the StopCmd and PauseCmd methods. This functionality would be in addition to the "should_stop" data member that is set to true before the mutex lock is attempted.
John has provided methods to do this.
I'm simply filing the issue so that we have a record of this work.