xlsconv 2.0 alpha

xlsconv 2.0 alpha is a preview of the next major version of xlsconv. This release includes a number of breaking changes for compatibility with wq 2.0 alpha. If you are only using xlsconv to generate models.py (and are not integrating with the wq framework), these changes should not affect you.

All changes by @sheppard.

Breaking Changes

• Drop all support for wq's old jQuery Mobile / Mustache renderer and HTML templates (38b6869).
  • xlsconv's xls2html(), html_context(), and render() methods have all been removed.
• Leverage the updated wq.db.rest API instead of the wq.db.patterns module, which was removed in wq.db 2.0 alpha (9f52275).

Other Fixes

• Don't import grouped fields as a separate model class in serializers.py (48a3243)
• Switch to pyproject.toml and test with latest Python versions (6a90a48)