prune: replace --biject with --pair People have been complaining about `--biject` being to obscure for a while. A recent discussion with Pulkit Goyal and Dan Villiom Podlaski Christiansen produce some new concrete proposal that we liked. We eventually settle on using `--pair`. The `--biject` flag will be kept as an alias for a while.

test-drop.t
test-inhibit.t
test-simple4server.t
tests/test-simple4server-bundle2.t