Support for nginx >= 0.7.65, add factor fact for nginx version, and template variable format

I've added support for older versions of nginx, to do this I needed a factor fact do detect the version and write config based on the version. I also fixed the variable formatting in the templates to include @ at front to stop puppet from bugging me about depreciation.

Also fixed a recent issues, missing ssl_session_cache/ssl_cache parameter to vhost resource and corresponding documentation.