Closes#274. Utxos are disabled if they are sent
to a reused address, and are below a threshold
set by the value `max_sats_freeze_reuse` in the
`POLICY` section of the config file. If the value
is -1, such utxos are always frozen irrespective of
the value.
Users are prompted with a warning level logging message
on CLI and a popup on Joinmarket-Qt. Such disabled utxos
can of course be re-enabled by the existing methods.
Also adds test case for address reuse freezing function.
Use relative paths when setting btcconf default filepath
Whitespace and newlines
Must specify return value in python
os.path.join preferred over str +
Also adding some print statements.
Adam Gibson
mecampbellsoup