Grey out inactive settings

[zachmueller]

In certain settings (main example is logging settings), it could make sense to grey out the extra settings that are there if they are "inactive" (in the case of logging, that feature is not active unless the user provides a filename for the log file). Check other plugins to see whether they do something like this and, if so, how they go about it. In the case of the logging settings, I could opt to have them hide completely while the log filename input is blank.