- Minor changes to cleanup some of the compiler warnings

- Deleted `NativeInfo` (internal class, not used anywhere)

- Removed some unnecessary `ToArray` calls
 - Initial pass on LLamaStatelessExecutor, the context overflow management is broken but I think I found where it's ported from

- Integrated grammar into sampling
 - Added a test for the grammar sampling

The biggest single change is renaming `LLamaModel` to `LLamaContext`

Fix serialization error due to NaN

- Also refactored it to return an `int[]` instead of an `IEnumerable<int>`, solving the "multiple enumeration" problems at the source!