Using `listfowards` for this wrong; expose this directly if people
care (and unlike listforwards, which could be deleted, we have to
remember these while the channel is still open!).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `listhtlcs` new command to list all known HTLCS.
Rusty Russell