Refactor to unify underlying http client to single class library

The current release of the openshift-restclient-java, for not so obvious reasons, depends on no less then 3 libraries to provide the underlying communication to the cluster server. Refactor dependency to a single client which is based on OkHttp. We are looking to make this change to:

• Provide a common way to make REST calls
• Simplify the authorization semantics to an openshift cluster
• Simplify the pattern of making REST calls over what is done today
• In future, take advantage of its SPDY support to move away from the oc binary dependency
• Put us in a better position to move to the Fabric8 client (if that ever happens)