Fixed models to correctly handle Data Uri's for embedded resources.
Removed png image for embeddedDuck model since the model resources are embedded. Also Model._baseUri behave as it should when no basePath is specified.
Fixed Uri resolving for resources to use toString(). Added dae file for test models.
Merge pull request #1788 from tfili/model-datauri

Fixed models to allow use of Data URIs for resources.
Merge master to refdoc-2