Add CoffeeScript spawn support and divide armyGo into two functions, addJob() and start()

I wanted to add jobs incrementally and splitting `armyGo` into two functions seemed the easiest for my use case.  Here's a pull request to show that work.  I didn't get into the gory details and so my changes handle only the simple case of:

  - call `addJob()` N times
  - call `start()`

as opposed to this case:

  - call `addJob()` M times
  - call `start()` 
  -  `process.nextTick( function(){ call addJob() N times   })`