These intermediate structs were creating unnecessary noise. The peer id
and multiaddr fields are going to be removed in the future further
reducing the need to have seperate structs for cancel, resume and
refund.
If the current balance is 0, we wait until the user deposits money
to the given address. After that, we simply swap the full balance.
Not only does this simplify the interface by removing a parameter,
but it also integrates the `deposit` command into the `buy-xmr`
command.
Syncing a wallet that is backed by electrum includes transactions
that are part of the mempool when computing the balance.
As such, waiting for a deposit is a very quick action because it
allows us to build our lock transaction on top of the yet to be
confirmed deposit transactions.
This patch introduces another function to the `bitcoin::Wallet` that
relies on the currently statically encoded fee rate. To make sure
future developers don't forget to adjust both, we extract a function
that "selects" a fee rate and return the constant from there.
Fixes#196.
