Logging

[rkaw92]

We need some legitimate logging support. The current solution, being the --debug CLI option, has several drawbacks; the final implementation should at least:

• [ ] Show zabbix_sender invocation parameters and results/exit codes if requested
• [ ] Dump the initially-loaded data (process list) for manual inspection
• [ ] Notify of inbound process events (start/stop)
• [ ] Notify of PM2 polling attempts and results
• [ ] Notify of PM2 daemon checks and results
• [ ] Use a standard format for its output

[rkaw92]

Planning to use bunyan for logging. Just forked node-zabbix-sender so that we can replace the built-in logger.

[rkaw92]

Logging has been vastly improved for v0.3.0.