Ordering of —log-dest and —mode matters, but shouldn't

[mhucka]

The way that Click parses arguments ends up causing the order of arguments to matter. For IGA, I ended up having to make --log-dest and --mode both "eager" arguments (in Click terminology); click parses eager arguments in the order they're given on the command line, which is a problem because changing the mode changes the details of how logging is done. If you pass --log-dest first, then --mode doesn't work as expected.