Use a parent parser to initialise subparsers.
Use a parent parser to initialise subparsers.

This is so help messages for subcommands contain all positional
arguments.

NOTE: this changes the order of positional arguments.  Sorry!

hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,ruthfranklin/hande,hande-qmc/hande,hande-qmc/hande