Classifier-free guidance

[abb128]

Classifier-free guidance was implemented in llama.cpp in ggml-org/llama.cpp#2135, but it doesn't look like there's a way to use it with these bindings. It seems like a useful feature, so it'd be nice to have this

[abetlen]

@abb128 totally, the low-level api is implemented for this but not the high-level api, I'll add it to the v0.2 roadmap

[apolinario]

Gentle bump feature suggestion for the high level API as the text-to-music model YuE uses CFG https://github.com/multimodal-art-projection/YuE