Added most important pieces of metadata for publication

This fixes what's more important about #106.
See [Returning metadata about the document](https://github.com/w3c/specberus/blob/tripu/issue-106-metadata/README.md#returning-metadata-about-the-document) for more information about the way metadata is returned.
For consistency with the rest of the code I have seen so far, I would wrap the `if` and `else`'s bodies with curly brackets.