This commit adds the fee negotiation procedure performed
on channel shutdown. The current algorithm picks an ideal
a fee based on the FeeEstimator and commit weigth, then
accepts the remote's fee if it is at most 50%-200% away
from the ideal. The fee negotiation procedure is similar
both as sender and receiver of the initial shutdown
message, and this commit also make both sides use the
same code path for handling these messages.
This commit adds the +build !rpctest build flag to the test files in
the main package other than the RPC tests. With this, if the protest
build flag is set, then ONLY those tests will be run.
Persists the state of a channel opening process after funding
transaction is confirmed. This tracks the messages sent to
the peer such that the process can be continued in case of a
restart. Also introduces that the receiver side forgets about
channel if funding transaction is not confirmed in 48hrs.
