Support for Fuzzy Searching Strings

The chosen library has been great to work with so far. While working on a project I came across a use case where I needed a more flexible search on the options in a select box.

This change set addresses that issue by implementing a sort of fuzzy search across the options. 

I'm no expert in CoffeeScript, so feel free to pull the code apart or suggest modifications.

##### Example

With the select box of:

```html   
<select data-placeholder="Your Favorite Types of Bear" class="chosen-select" multiple>
  <option value=""></option>
  <option>American Black Bear</option>
  <option>Asiatic Black Bear</option>
  <option>Brown Bear</option>
  <option selected>Giant Panda</option>
  <option>Sloth Bear</option>
  <option>Sun Bear</option>
  <option>Polar Bear</option>
  <option>Spectacled Bear</option>
</select>
```

Searching `Sp Bear` or `Bear Sp` will show  `Spectacled Bear`
@koenpunt I removed the .map() function. I guess I didn't look at the IE 8 compatibility.