Turn Ezel into a project generator

This makes maintenance of Ezel easier by turning it in to a command-line project generator like Express's express-generator. It's also is nice b/c it leaves out the README/LICENSE files from generated projects and lets the "clean" version of an Ezel boilerplate be cleaner by leaving out snippets of code hard to remove from simple `rm`s.

From now on generating an Ezel project will use the Ezel CLI `npm install -g ezel`. Some of the commands include:

````bash
ezel myapp # A new javascript Ezel example project using the Github API
ezel --clean myapp # A clean JS Ezel project
ezel --coffeescript myapp # A coffescript Ezel example project
ezel --coffeescript --clean myapp # A clean CS Ezel project
````