Save Swagger documentation in HTML with editor styles

Following issue in detail describes the inability to export documentation from editor.swagger.io into static HTML.

This simple hack allows you to use the editor preview styles without the editor pane (as of August 1, 2018).

Simply point the config URL to your custom API definitons (.yaml or .json).

Also added extra options:

1. View the editor conditionally by adding /editor to the path
2. Persisting access tokens to save time
3. Ability to dynamically change the yaml config thorugh console by setting editor.CONFIG_URL = 'your_config_url'