Add new framing features.

- Allow filtering based on a specific @id.
- Allow ducktyping matches on @type: [{}].
- Allow ducktyping matches when a @default is specified.
- Add @requireAll flag for controlling ducktyping requirements.
Start 0.3.0.
Fix bug w/blank nodes across graphs and RDF lists.

- Addresses https://github.com/json-ld/json-ld.org/issues/357.