Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

Signed-off-by: Lukas Reschke <lukas@statuscode.ch>

Signed-off-by: Lukas Reschke <lukas@statuscode.ch>

Fix an issue with APCus inc and dec methods on PHP 7

see https://github.com/krakjoe/apcu/issues/183#issuecomment-244038221 for details

* allow configuration of memcache options

Use production values for memcached as explained in http://apprize.info/php/scaling/15.html

The current implementiation uses ascii based serialization. This PR should reduce traffic to the memcached server.

cc @MorrisJobke @FelixBoehm

* add config sample

* merge config options, throw hint on config error

* fix typo

* fix config sample