Added support for SSL

So, this adds SSL / HTTPS support. It's an hackish thing though, so Im not sure if you should merge this :)

Basically we generate a dummy SSL certificate, then allow traffic on port 443 for every host.

I will use this within our dev infrastructure as we need a simple way to boot new environments locally and let nginx discover them, on both HTTP and HTTP but I think that a more elegant solution would be to add a `-e PROTOCOL=http,https` on the other containers and generate the according configuration through docker-gen.

Lmk your thoughts...cheers!