`assume_ssl` and `force_ssl` are often used together:
- When running behind a terminating proxy (including Thruster) you'll
want both.
- When running without SSL (like on localhost) you'll want neither.
To simplify setup for those cases, we add the `DISABLE_SSL` option. When
set to `true` all SSL-related behaviour is turned off. When left as the
default, it's on.
We can still use `ASSUME_SSL` and `FORCE_SSL` to set those separately
if required.
Kevin McConnell
154a3d79ee