Since `this` was captured, it does not need to be specified, but GCC 6
can't do it.  Since we want to support the standard compiler from
Debian Stretch (stable), we need to work around this problem:

 src/neighbor/plugins/UdisksNeighborPlugin.cxx:239:12: error: cannot call member function 'void UdisksNeighborExplorer::Insert(UDisks2::Object&&)' without object
       Insert(std::move(o));
       ~~~~~~^~~~~~~~~~~~~~

This fixes #300 which I previously thought was a different bug.

Sometimes, the JVM returns a non-nullptr value with an exception
pending (seen on Android 1.6, maybe a Dalvik bug?).  Let's catch all
such cases.

The new implementation is copied from another project and is
BSD-licensed.  It is exception-safe and can parse IPv6 scope ids with
interface names.