Currently use of a proxy such as nginx to force https usage results
in a bit of loopiness. This patch adds the sslproxy setting and when
this is set, mandates that the wwwroot be a https address.

Change-Id: Ic4cfe048202cea60098e60e57adb99a0cb594619
Signed-off-by: Melissa Draper <melissa@catalyst.net.nz>