include openai o1 models

[williamjameshandley]

openai released its o1 'reasoning' models this week. It would be great to incorporate these.

I think that this is relatively straightforward (suggested PR: #89 modelled on this commit d90b1b9), but it does open some interesting questions for more fine-grained pricing reports. The new models now provide information for how many tokens were used for reasoning in the completion_tokens_details.

[kharvd]

fixed in #89