NeuterFilter does not support coffeescript

lib/main.js

``` ruby
require("a.js")
```

lib/a.coffee

``` ruby
console.log("a.coffee")
```

Assetfile

``` ruby
input "lib" do
  match "*.coffee" do
    coffee_script
  end

  match "main.js" do
    neuter "app.js"
  end
end
```

```
$ bundle exec rakep
> can't find lib/a.js
```
