Update _llama_cpp.py to use new bindings

[nking-1]

The newest version of llama_cpp bindings breaks a few lines of code due to changed variable names and function signatures. I've attempted to make a fix that will be backwards compatible for people using the older version of the llama_cpp library while also working with the new one.

This PR will fix issue #659

[Harsha-Nori]

Thanks for this fix @Nking92! Our CI pipelines can't do this, but we should test the backwards compatibility on an env with say

pip install llama-cpp-python==0.2.47. Do you mind downgrading your llama-cpp-python and testing the fix in your environment? I'll do the same on my end.

given how frequently llama-cpp-python (and the underlying llama.cpp) introduces breaking changes, we may want to consider specifying versions in our setup.py

@slundberg FYI

[nking-1]

Thanks Harsha, I tested with llama-cpp-python==0.2.47 this morning without having any issues.

[Harsha-Nori]

Per llama-cpp-python, I think the function signature here didn't change -- did we figure out why there was an issue with using named args instead of positional ones here?

https://github.com/abetlen/llama-cpp-python/blob/8c71725d5345b2ba325e6d28209875057c5873e6/llama_cpp/llama_cpp.py#L1645

[Harsha-Nori]

In any case, changing this seems to work -- just curious about why! LGTM