libmemcached Versioning

Libmemcached is laid out by interface version. The 1.0 version would be found in: libmemcached-1.0/memcached.h

The historic libmemcached/memcached.h includes libmemcached-1.0/memcached.h. For best practice you should include the version of libmemcached that you used during development.