In this commit, we attempt to fix an issue that may lead to force closes due
to small value HTLCs. The sweeper has built in a "negative yield" heuristic
where it won't sweep something that'll result in paying more fees than the
HTLC amount. However for HTLCs, we want to always sweep them, as we don't
cancel back the HTLCs before the outgoing contract is fully resolved.
In the future, we'll start to make more uneconomical decisions about if we
should go to chain at all for small value HTLCs, and also do things like
cancel back early if the HTLC is small and we think we might be contested by
chain fees.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
In this commit, we take an initial step towards converting the existing
breach arbiter and utxo nursery logic into contract resolvers by moving
the files as is, into the `contractcourt` pacakge.
This commit is primarily move only, though we had to massage some
interfaces and config names along the way to make things compile and the
tests run properly.
