Dendron

Dendron should start to work better on CPU-only systems.

- Avoid loading bitsandbytes when not quantizing models in CausalLMAction (dansbecker).
- Avoid loading bitsandbytes when not quantizing models in ImageLMAction, CompletionCondition (RichardKelley).

Getting Dendron playing nicely with Apple systems is now on the horizon.

Added support for emitting log probabilities from a `CompletionCondition` node.

Added support for ViP-LLaVa. In so doing, created a mechanism to easily add support for new vision-language models in the `ImageLMAction` node.

Updated language model nodes to properly use BitsAndBytes configuration. This should remove deprecation warnings.

Updating README.