Option -X now makes it possible to stop YAZ proxy by sending

"stop" as PROXY target (in init). This used to be debug code in a
#if 0 .. #endif section.

Moved a lot of "private" stuff to proxyp.h so that only Yaz_Proxy
is publicly defined in include/yazproxy/proxy.h.

Authentication info sent to target modified. Element renamed from
"authentication" to "target-authentication" to avoid confusion with
client authentication. It now takes an authentication
type=open|idPass|anonymous . Value is user:group:password for idPass,
user/pass for open. Option -U auth is no longer supported.