Probe: make usable with TCP based configuration

Probe currently requires IP multicasting. The goal is to also be able to use probe.sh with TCP based configs.
SOLUTION:

• Specify one or more IP address:port pairs when starting probe.sh
• probe.sh will connect to all provided addresses in turn until one responds
• The response contains the requested information and the full list of all member addresses
• probe.sh then contacts all members (excluding the ones from which it already received information)