Enforced via the newly added `clippy::mod_module_files` lint.
Previously a mixture of 2015 (`mod.rs`) module files along with
the 2018 `foo.rs` and `foo/` approach.
All of the toplevel modules (`edwards`, `field`, `montgomery`, and
`scalar`) were using the 2018 convention, except for `backend`,
`ristretto`, and the recently added `lizard` were using the 2015
convention.
This renames the files so everything follows the 2018 convention, and
applies the afforementioned clippy lint which will error if anyone tries
to add new files using the 2015 convention.
* Vendor lizard hash to curve from Signal
* Add invalid Lizard encoding test
* Added lizard details to readme and changelog
* Upgrade ristretto.sage to Python3
* Add lizard test vector generation to ristretto.sage
* Added map_to_curve and its inverse
* Use CtOption instead of bitmasks; other cleanup
* Add README to lizard folder
* Split map_to_curve into map_to_curve and map_to_curve_restricted; make its inverse return 16 elements
* Consolidate Ristretto Elligator functions into its own file