Added support for forwarding Secure Group Tags (SGT) on traffic. This is available on Z3(C), MX64(W), MX65(W), MX67(C,W), and MX68(W,CW), MX75, MX85, MX95, MX100, MX105, MX250, and MX450 appliances and enables full stack (MR+MS+MX) Adaptive Policy operation.