Ckipnlp

- Fix encoding error in setup.py.

- Update copyright and license.

- Add JSON serialization methods to utility objects.

- Update CKIP-Parser utility objects.
- Rename `ParserNode` to `ParserNodeData`
- Add new `ParserNode` for `ParserTree.node_class`
- Update `ParserRelation` fields.

- Fix ParserTree input. [2]
- Update documentation. [3]

- Update documentation.

- Add utilities.
- Add word segmentation utilities.
- Add sentence parsing utilities.
- Add relation utilities (from sentence parsing).

- Update package structure.
- Deprecate `ckipws` and `ckipparser`. Use `ckipnlp.ws` and `ckipnlp.parser` instead.
- Deprecate `ckipws.CkipWS`. Use `ckipnlp.ws.CkipWs` instead.

- End support to Python 2.