Does server mode work? Does it make sense?

[sodabrew]

Following up from #418: I haven't personally tested server protocol support, and I don't see unit tests for it. I'm not sure what the use case would be for the PHP module. Existence of this code predates my role as maintainer.

The libmemcached library has to be compiled to provide server protocol support; by default (and in most distributions) it is disabled:
https://bazaar.launchpad.net/~tangent-trunk/libmemcached/1.0/view/head:/configure.ac#L81

AC_DEFUN([LIBMEMCACHED_PROTOCOL],
         [AC_ARG_ENABLE([libmemcachedprotocol],
                        [AS_HELP_STRING([--enable-libmemcachedprotocol],
                                        [Enable libmemcachedprotocol])],
                                        [ax_enable_libmemcachedprotocol=yes],
                                        [ax_enable_libmemcachedprotocol=no])

         AM_CONDITIONAL([BUILD_LIBMEMCACHED_PROTOCOL],[test "$ax_enable_libmemcachedprotocol" = "yes"])

         AC_MSG_CHECKING([for libmemcachedprotocol])
         AC_MSG_RESULT([$ax_enable_libmemcachedprotocol])
         ])
LIBMEMCACHED_PROTOCOL

Purpose of this ticket is either to add tests demonstrating that this mode works or consider removing it.