Lix commit 4dbbd721e[1] changed the way settings are changed, removing
operator= in the process. This commit changes the places where we use
operator= to using either setDefault(), or override(). I *believe* I
have used the correct ones for each changed setting.
Fixes#13.
[1]: 4dbbd721eb9db75d4968a624b8cb9e75e979a144