Opendp

Changed
- All unvetted modules (which is currently all modules) are tagged with the "contrib" feature
- Programs must explicitly opt-in to access the "contrib" feature

Fixed
- Version tag

Fixed
- Version tag

Added
- User guide, developer guide, and general focus on documentation
- Examples folder has complete notebooks for getting started with the library

Fixed
- Usability issues in the FFI layer for `make_count_by_categories` and `make_count_by`
- The FFI for make_identity ensures proper domain metric pairing

Added
- Functions to convert between accuracy and noise scale for laplace, gaussian and geometric noise
- Error messages when chaining include a plaintext description of the mismatched domains or metrics

Added
- User guide outline
- Initial exemplar python notebooks
- Binary search utilities in Python
- `Vec<String>` and `HashMap<K, V>` data loaders
- Resize transformation for making `VectorDomain<D>` sized
- TotalOrd trait for consistency with proofs

Changed
- General renaming of library interfaces. [See issue 181](https://github.com/opendp/opendp/issues/181).

Removed
- Scalar clamping

Fixed
- Adjust output domain on `make_count_by_categories` to make it chainable with measurements