Set reuse address option (fixes #1043)

When the server is killed there may still be client-sockets connected in
the TIME_WAIT state, causing the bind() call to fail. With the
REUSEADDR option we can reuse the address immediately unless another
process is actually *listening* on the same address.
that we want to reuse the address
Merge pull request #1053 from andkit/fix-1043

Set reuse address option (fixes #1043)