M142 extended agentctrl script so it can initiate reach back.

@edwardhunter can you please review.

Tested with "SBE Simulator" instrument device.  For this instrument preload is currently using v 0.1.3 of the SBE3 driver.  Reach back initiation will fail until that driver is bumped to 0.1.6.

Also it made life much easier for me to have this script start an instrument agent so I added that ability.  To run and test this feature:

1. Start the container
bin/pycc path=master --rel res/deploy/r2deploy.yml –mx

2. Preload beta
bin/pycc -x ion.processes.bootstrap.ion_loader.IONLoader op=load scenario=BETA path=master attachments=res/preload/r2_ioc/attachments loadui=False

3. Start the IA
bin/pycc -x ion.agents.agentctrl.AgentControl instrument="SBE Simulator"

4. Initiate Recovery
bin/pycc -x ion.agents.agentctrl.AgentControl instrument="SBE Simulator" op=recover_data recover_start=0 recover_end=1

5. Stop the IA
bin/pycc -x ion.agents.agentctrl.AgentControl instrument="SBE Simulator" op=stop