We need to know what the lease we're expecting is. To do this
we pass around the hex encoded portion of the wire format.
We can use this passed in expected lease rates to confirm that the peer
is, in fact, using the same rates as what we have currently.
Changelog-Added: JSON-RPC: fundchannel, multifundchannel, and openchannel_init now accept a 'compact_lease' for any requested funds
Finally, extends the 'close_to' functionality up to the flagship 'open a
channel' command.
Changelog-Added: JSON-API `fundchannel` now accepts an optional 'close_to' param, a bitcoin address that the channel funding should be sent to on close. Requires `opt_upfront_shutdownscript`
