Salesgpt

- "use_tools" as a keyword argument (kwarg) is treated as STRING i.e., agent_config["use_tools"]="True"
to be consistent with JSON payloads.
- add asynchronous streaming generator.

August 18, 2023
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- SalesGPT API - added chat as a service and Chinese language SalesGPT prompt, huge thanks to janewu77!

July 29, 2023
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- Minor update, remove unneccesary verbosity from `SalesGPT.from_llm` method.

July 15, 2023
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- Added tools to SalesGPT, creating a true agent.
- Added product knowledge base as an example tool

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