Reynir

Support for new token types: ``TOK.DATEABS``, ``TOK.DATEREL``, ``TOK.TIMESTAMPABS``, ``TOK.TIMESTAMPREL``, ``TOK.MEASUREMENT``. Extended grammar support for date and time phrases. Added ``SimpleTree.top_matches(pattern)``, and the tree properties ``nominative``, ``indefinite``, ``canonical``, ``nominative_np``, ``indefinite_np``, and ``canonical_np``. Documentation and test suite updates.

This release adds the `SimpleTree.all_variants` property. Python-side parse tree construction from the C++ tree is now faster since empty nodes are now immediately translated to `None`.

Update to the child coalescion code in `fastparser.py` to fix error when parsing certain sentences.

Fixes bug in parsing code in `fastparser.py` that caused some complex sentences to raise an exception during parsing. Minor updates in README.rst and documentation.