new option for registration in place

[trel]

need the equivalent of ireg to register existing data at rest.

possible flag...

• -r for register only (preferred... but possibly confusing due to 'recursive')
• -c for catalog only

also...

• need to make sure the iRODS server is the same as the client machine.
• need to ignore/complain about the -K flag (or seamlessly downgrade to only -k)