RFC 3339 Date/Time Utilities

The `tonyg-rfc3339` library provides a Python implementation for parsing and formatting dates and times according to RFC 3339. It includes `tzinfo` classes for UTC and fixed-offset timezones, aiming for simple, standard, and robust timestamp handling across languages. The current version is 0.1, with its last PyPI release in 2015, suggesting a maintenance or stable status rather than active development.