Graphbrain

Added
- claim_actors and corefs_dets agents.
- meaning.concepts module.

Changed
- Fixed example.
- hypergraph.sum_degree() and .sum_deep_degree().
- Parser improvements.
- Agent corefs_atoms is now corefs_unidecode.
- Improved docs.

Removed
- Obsolete 'work-in-progress' code.
- hg2json command.

Added
- Primary entities and deep degrees.
- Hyperedges have their own class, deriving from tuple.
- Atoms have a special class, deriving from Hyperedge.
- Restructuring of code files tree.
- Created agent system + first agents.

Changed
- Parsers now have own package.

Removed
- Old experimental code.

Added
- First release.