First pass

modularize scaffolding for node cluster

currently projects like cn, rtapi, ncar, pds all have a variant of this

please provide opinions

@Raynos @mrhooray @jsu1212 @kumikoda 
This is a library, we should not pass in loggers to this library as it means library authors put noise in the application logfiles that application authors use.

The current recommendation for an alternative is to use `debuglog` like used in typed-request ( https://github.com/uber/typed-request/blob/4aad30ed88f3037f76349beb0df89d85712ebba0/index.js#L2 ).

In the future we may have a nicer library logging experience then `debuglog`.

If you wish you may also use debug instead ( https://github.com/visionmedia/debug ).