Downgrade logging statements.

Update dependencies.

Remove unnecessary log statements in conversation_test.go, cached.go, and poet.go

Removed unnecessary file.

Document Anthropic.

Remove token counters.

OpenAI and Anthropic implement retryable errors.

go mod tidy

retry uses the notion of retryable errors.

Memory now takes a tokenizer.

Tokenizer implementation for Anthropic and OpenAI.

Moved anthropic to exp.

Model constants for Anthropic.

Streaming implementation.

First implementation of the Anthropic client.