make chefs choice option

By default, the following options are chosen:

```js
this.newDirectory = true;
this.includeCoffeeScript = false;
this.useZepto = false;
this.starterApp = "Hello World";
this.styleProcessor = "less";
```

- make prompt for a new directory name come directly after choosing
  new directory, if directory names collide, this happens for
  both chefs choice and extended prompt
- add documentation about the prompts

fixes #89