SSL improvements (default ciphers & caching), server_tokens option, and proxy_set_headers for vhosts

This is a backwards compatible set of changes.

Changed the default ciphers for SSL to be more secure (the ones in use were vulnerable to the BEAST attack)
Added SSL caching to speed up SSL requests
Add server_tokens to the global config so this can be turned on|off between dev and prod
Add proxy_set_header to vhost as different vhosts may require different headers and the global setting is not ideal
Minor space formatting so that the generated files are fractionally more readable