Add a script to read from the asset pipeline on the command line

```
Jon-Gilbraith-000782:frontend[asset-script*]$ script/read_asset
Usage: read_asset -a <asset path> [other options]
    -a, --asset ASSET_PATH           The asset path of the asset you wish to read (as would be passed to the asset_path helper).
    -f, --path-format FORMAT         'URL' will return asset paths in url format, 'FILESYSTEM' (default) will replace those with filesystem paths
Jon-Gilbraith-000782:frontend[asset-script*]$
```

The idea behind this is to have something that the native javascript testing frameworks can shell out to in order to retrieve erb based items from the asset pipeline.