It is now possible to perform a mux between two points or between two non-identity points.
`mux(choice, left, right)` will return `left` when `choice=0` and `right` when `choice=1`.
`choice` must be constrained to `{0, 1}` outside the gate.
It is no longer needed to expose `from_coordinates_unchecked`.
Short range checks on 4 and 5 bits are now performed with only one lookup (instead of 2).
To do that, we added a column `table_short_range_tag` in the lookup table.
This new column `table_short_range_tag` contains the value
- 4 for rows used in short range check on 4 bits
- 5 for rows used in short range check on 5 bits
- 0 for rows used in short range check on 10 bits
Disable tests on i686 and code coverage in CI
- The crate module structure from `orchard` has been flattened.
- The book pages we want to include in `halo2` have been moved to their
target location, to avoid any conflicts during the merge.
- Common files that already exist in zcash/halo2 have been removed.