* split, regroup, and async'ify files
* consistent window scrolling in scrollToEditor and jumpToPos
* rework waitForSelector and collapsible <details>
* parserlib: fast section extraction, tweaks and speedups
* csslint: "simple-not" rule
* csslint: enable and fix "selector-newline" rule
* blank paint frame workaround for new Chrome
* extract stuff from edit.js and load on demand
* simplify regexpTester::isShown
* move MozDocMapper to sections-util.js
* extract fitSelectBox()
* initialize router earlier
* use helpPopup.close()
* fix autofocus in popups, follow-up to 5bb1b5ef
* clone objects in prefs.get() + cosmetics
* reuse getAll result for INC
* also apply live-preview if an unsaved style was disabled
* use box-shadow instead of outline for focus everywhere
* allow focus outline on click in text/search input or textarea
* search inputs should use the same style as text inputs
* also use box-shadow focus on delete buttons
* remove URLSearchParams workaround, not needed since Chrome 55
* use `once` in addEventListener, available since Chrome 55
* update USO bug workarounds, remove obsolete ones
* ping/pong to fix openURL with `message` in FF
* use unprefixed CSS filter, available since Chrome 53
* use unprefixed CSS user-select, available since Chrome 54
* focus tweaks
* also use text query in inline search for Stylus category
* use event.key, available since Chrome 51
Co-authored-by: narcolepticinsomniac
