Changes in style to make widget footer sticky to the bottom
Changes to make possible the rendering of image from metadata and validating it through parameters
parameters is added to the data_dict for widget rendering
Merge pull request #16 from CodeandoMexico/image_widget

Image widget is now possible with parameter banner=true and dataset_image metadata.

Now you can render a banner to embed a dataset by adding a parameter banner=true in the URL and adding a valid image url in the metadata schema.

I.e.
key should be: dataset_image
value: http://example.com/image.jpg