Need to track+log stderr/stdout for the sub-process

[opaugam]

• we often need to quickly see what's wrong with the process controlled by ochopod (trying debugging a glitch in Kafka otherwise...).
• we need to pipe stderr/stdout from the POpen()'ed process into either /var/log/ochopod.log or another file, whatever.
• both logs should be available via HTTP POST /log on any ochopod container.

[opaugam]

lillio is actually working on that one..