Added section About 2013 Security updates.

Mentioned new platform tunneling feature added in AX-3.5 and added reference to Appendix C, NiagaraAX-3.5 Platform Guide.

Changes were made throughout this document to reflect the “Only Tunnel Known Stations” and “Proxy Authentication When Tunneling properties added with NiagaraAX-3.4.

Main section links were added to the first page.

Initial publication.