Support for O1 models

Merge pull request #10 from ando-masaki/o1-preview-and-mini-fix

Added o1-preview and o1-mini

Added support for GPT-4o and o200k base models

This release adds support for the latest models from OpenAI

Lazy loading maps

Vocabulary maps are now lazy loaded when use for the first time. This should minimize the amount of memory consumed and start-up time.

v0.0.8: 🪄 clean up the bpe algorithm

Renamed variables struct to reflect what they do a little better.