Added three generic user-interpretable server failure reasons
Added three generic user-interpretable server failure reasons

Summary: Users of this library may desire more than the available server error types.  For that reason, three generic types were created that can be interpreted by users in a manner of their choosing.

Test Plan: http://jenkinsmaster.mediamiser.internal:8080/job/mercury-protobuf-activemq-rpc-chris/40/

Reviewers: samer.albuhaisi

Reviewed By: samer.albuhaisi

Differential Revision: http://phabricator.mediamiser.internal/D1180

MediaMiser/protobuf-activemq-rpc,MediaMiser/protobuf-activemq-rpc