Remove references to 'model_file', getting model name from template name

![ski](https://f.cloud.github.com/assets/527874/2098824/100fef44-8f33-11e3-93e9-31f607828580.gif)

This PR removes the need to pass in 'model_file' as an option, the name of the model will be the same as the name of the template being rendered.