Commander: status changes.
Commander: status changes.

- Added 'st' alias.
- Restricted status output to core status only, unless the target is locked.

mbedmicro/pyOCD,mesheven/pyOCD,mesheven/pyOCD,flit/pyOCD,pyocd/pyOCD,flit/pyOCD,mbedmicro/pyOCD,mesheven/pyOCD,pyocd/pyOCD,mbedmicro/pyOCD