Fixed Bluewing; DarkEDIF properties now work

Fixed abusive problems whereby disconnecting peers/closing channels were
still write-accessible in Bluewing; these now have a flag to show if
they are closing, allowing you to read the channel/peer name on
disconnect events but not afterwards. This means the unsightly hack is
no longer necessary, and liblacewing code is still clean.
Fixed bugs in properties, now uses a stream of data (std::stringstream)
to queue all information and overwrites cleverly.

Note that for compatibility with the regular Lacewing Relay, properties
in Bluewing are still implemented manually, bypassing the automatic
DarkEDIF properties.