Added json tags to ConnectOpts to make it serializable
Added json tags to ConnectOpts to make it serializable

Added `json:"whatever,omitempty"` tags to ConnectOpts fields to make it (de-)serializable to/from json.
dancannon/gorethink,GoRethink/gorethink,dancannon/gorethink,dancannon/gorethink,GoRethink/gorethink,GoRethink/gorethink