App now better understands SSL

Still a long way from finished, but now analytics (Omniture) understands http and https

Images now understand https

During local development the nginx will now forward the X-Forwarded-Proto header like an ELB does
We have been quite bad at it, but the spirit of our config is that we only configure things that change between environments or that are secrets. Other things go straight in the code and if they need to be re-used then inside a sensible abstraction (which I hope that `AnalyticsHost` is).

I'm going to start ripping config to pieces soon.