Add a Simple Twemproxy compatible KetamaNodeLocatorConfiguration support...

...ing uniform weighting.

I've created a utility KetamaNodeLocatorConfiguration that is compatible with the Twemproxy implementation of Ketama in nc_ketama.c provided that the servers are weighted uniformly.  The patch also modifies the ConnectionFactoryBuilder to expose a method for a client to set an alternative configuration object on the Ketama locator object.