Followup to @littlesweet's MR !299. Refactoring prior to taking on issue #27.
Edit: This MR was supposed to target the branch from MR !299. But the way I submitted it, it's targeting master instead. Please review only the eponymous top commit, the rest will disappear once !299 goes into master and this MR gets rebased on top of that.
This commit should be a no-op functionally, and prepares forforking backlight functionality into Linux and FreeBSD versionsinside the daemon as well (not just the KAuth helper).