Batch of API changes

1. More sophisticated method of adding entries for all sub layers. Previously, the layer code looked for child layers by comparing label_ids. This was patched to handle interpretations, but with subparts we needed something a little more sophisticated.

Now, when a layer is added, this recursively looks at all children of the associated regulation node and adds layers as appropriate.

2. Pretty print is now off. This shrinks the size of json sent considerably

3. Add an end point for listing versions of a regulation

4. Add a filter for notices, filtering by regulation part

5. Add effective date, publication date, and FR url to the listing of notices (this allows them to be collected by the UI)