Feature/add gomemcache

Add optional golang based gomemcache library. 
This library does not require libmemcached, and provides it's own pooling, but does not offer the level of control that gomc does. This library has NOT yet been fully load tested.

@bbangert || @kitcambridge r?
It did indeed. We need to make sure that @oremj understands that starting the new app only requires ```simplepush [-config <config file>]``` where <config file> is not config.ini