Proxy fixes

[Alan DeKok]

  I managed to find an hour or two in between various things.  I've
taken a look at the proxy code, and added some fixes in "master".

  To be polite, I didn't quite understand the previous code. So... I've
deleted things, and simplified other things.  The result is that the
"zombie" home server detection should be better.

  I don't know if it fixes the "crash on dead home server" issue that
people were seeing.  I wasn't able to reproduce that.  But, the relevant
code is now different.  So I hope it's fixed.

  As always, blame Arran for any bugs. :)

  Alan DeKok.