Solve issue #3510

Changing settingsCtrl.js and settings.jade to solve issue #3510:
1) When Show Header is checked, Sticky Header is enabled.
2) When Show Header is not checked, Sticky Header is disabled and not checked. I think there's no reason to enable it when you don't have a header to stick.
3) When show header is checked & sticky header is checked too, when you check Show Header browser will refresh and sticky header will go off.