Update the `bitcoin_tx_add_input` interface to accept a witness script
and or scriptPubkey.
We save the amount + witness script + witness program (if known) to
the PSBT object for a transaction when creating an input.
Previously we've used the term 'funder' to refer to the peer
paying the fees for a transaction; v2 of openchannel will make
this no longer true. Instead we rename this to 'opener', or the
peer sending the 'open_channel' message, since this will be universally
true in a dual-funding world.
The way we build transactions, serialize them, and compute fees depends on the
chain we are working on, so let's add some context to the transactions.
Signed-off-by: Christian Decker <decker.christian@gmail.com>
It's just a sha256_double, but importantly when we convert it to a
string (in type_to_string, which is used in logging) we use
bitcoin_txid_to_hex() so it's reversed as people expect.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The wire protocol uses this, in the assumption that we'll never see feerates
in excess of 4294967 satoshi per kiloweight.
So let's use that consistently internally as well.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
