* Use std::ops::Range of columns rather than arrays of column indices.
* Refactor reading from the local values table.
* The inevitable post-push fmt/clippy commit.
* First draft of 256-bit addition.
* Update comment.
* cargo fmt
* Rename addition evaluation file.
* Port ALU logic from SZ.
* Give a name to some magic numbers.
* `addition.rs` -> `add.rs`; fix carry propagation in add; impl sub.
* Clippy.
* Combine hi and lo parts of the output.
* Implement MUL.
* Suppress Clippy's attempt to make my code even harder to read.
* Next draft of MUL.
* Make all limbs (i.e. input and output) 16-bits.
* Tidying.
* Use iterators instead of building arrays.
* Documentation.
* Clippy is wrong; also cargo fmt.
* Un-refactor equality checking, since it was wrong for sub.
* Daniel comments.
* Daniel comments.
* Rename folder 'alu' -> 'arithmetic'.
* Rename file.
* Finish changing name ALU -> Arithmetic Unit.
* Finish removing dependency on array_zip feature.
* Remove operations that will be handled elsewhere.
* Rename var; tidy up.
* Clean up columns; mark places where range-checks need to be done.
* Import all names in 'columns' to reduce verbiage.
* cargo fmt
* Fix aux_in calculation in mul.
* Remove redundant 'allow's; more precise range-check size.
* Document functions.
* Document MUL instruction verification technique.
* Initial tests for ADD.
* Minor test fixes; add test for SUB.
* Fix bugs in generate functions.
* Fix SUB verification; refactor equality verification.
* cargo fmt
* Add test for MUL and fix some bugs.
* Update doc.
* Quiet incorrect clippy error.
* Initial implementation of ADDMOD and MOD.
* Fixes to addmod.
* Update doc.
* Do 1000 random tests instead of just 1.
* Documentation fix.
* Working version of ADDMOD.
* Working version of MOD.
* Name magic number; do multiple MUL tests.
* Add code and test for special case; add some docs.
* Fix spelling mistake.
* Simplify asserts.
* Tidy comment.
* Remove unused module.
* cargo fmt
* Check that output is reduced.
* Add conversion of canonical `i64` to a `Field64`.
* Handle zero modulus within degree constraint.
* cargo fmt
* Fix some comments.
* Check that the top half of the product is zero!
* Start of refactor.
* Refactoring.
* Remove zero and reduction handling from addmod.
* Refactoring; renaming; bug fixes.
* Reuse intermediate calculations across all modular operations; don't negate quot poly unnecessarily.
* Fix bug where last elt of q*m wasn't checked.
* Refactoring.
* Move circuit poly functions to utils.rs.
* Rename ADDMOD stuff to MODULAR.
* Rename module addmod -> modular.
* Handle zero modulus.
* Verify that output is reduced.
* Implement recursive version of modular circuits.
* clippy
* Tidy up i64 -> Field conversion following Jacqui's comments.
* cargo fmt
* Improved documentation.
* Address Jacqui's comments.
* Save some gates by using builder.arithmetic_extension().
