It's currently written to produce "local" commit-txs, but of course we
need to produce remote ones too, for signing.
Thus instead of using "remote" and "local" we use "other" and "self",
and indicate with a single "side" flag which we're generating (because
that changes how HTLCs are interpreted).
This also adds to the tests: generate the remote view of the commit_tx
and make sure it matches!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We used to have a permutation map; this reintroduces a variant which
uses the htlc pointers directly.
We need this because we have to send the htlc-tx signatures in output
order as part of the protocol: without two-stage HTLCs we only needed
to wire them up in the unilateral spend case so we simply brute-forced
the ordering.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
