### Changed
- API changes:
- `header` attribute renamed to `preamble` to avoid confusion.
- improved version header parsing to be more robust and handle multi-word version names.
- improved version number incrementing in `release`.
- can now handle other text surrounding a pep440-compliant version number, which will not be modified
- can now handle pre-releases correctly. The version to increment is the most recent version in the log with a valid pep440 version number in it.
- Release increment and prerelease increments can be mixed, allowing e.g: `yaclog release -mr` to create a release candidate with in incremented minor version number.
- `release` base version is now an argument instead of an option, for consistency with other commands.
### Removed
- `entry` with multiple `-b` options no longer add sub bullet points, instead adding each bullet as its own line.
### Added
- Terminal output has color to distinguish version names/headers, sections, and git information.
- Extra newlines are added between versions to improve readability of the raw markdown file.
