Dependencies #2
Description
It would be great if all the chapters worked right out of the box as node modules, so you can play with them at the node.js REPL or require() them into a temporary javascript file to play with.
For example, Chapter02 is dependent on truthy() and existy() and underscore.js, but you need to modify the chapter to make these available in chapter02.
Caveat: To make it easy to play with at the REPL, you may need to do something with _.noConflict since the node REPL uses _ to store the previous REPL value.