Deduce

Changed
- Internal code formatting improvements

Added
- Contributing guidelines

Fixed
- Bug with multiple 4-digit mg dosages in one text

Fixed
- Minor bug where tag flattening had no effect

Added
- Changelog
- Additional unit tests for whitespace/punctuation

Fixed
- Various whitespace/punctuation bugs
- Bug with nested tags not related to person names
- Bug with adjacent tags not being merged

Added
- Structured annotations
- Some unit tests

Fixed
- Error with outdated unicode package
- Bug with context

Release to PyPI