[Lightning-dev] Updates, move to Elements Alpha

[Rusty Russell]

Hi all!

        Those watching the repository late last week will note that the
code has gained ifdefs to support Blockstream's Elements Alpha
sidechain.  Along the way, there were some bugfixes as you'd expect.

        This is a stepping stone; done because it already has the
features LN wants which aren't soft-forked into bitcoin yet.  OTOH,
alpha contains many "cool features" we don't care about (like
Confidential Transactions), but made the port a bit trickier than I'd
hoped.

        I'm working on HTLCs now.  Because I'm using hashes for
revocation rather than exposing private keys (and because I'm using
OP_CHECKSEQUENCEVERIFY), they look different from the ones in the paper.
Once I've got something that's not obviously wrong, I'll post here.

Thanks,
Rusty.