* saveStyle: retain only known properties in sections[] and normalize their order
* remove styleDigest on import
* shorten detailed status names in updater
* don't autohide update status message
* Now filtering is done in js
* Visible entries are always at the beginning of #installed
* Hidden entries are always at the end of #installed
* The code tries to minimize DOM reordering operations:
* First pass only moves one hidden entry in hidden groups with odd number of items.
* Second [full] pass runs after repaint.
chrome://favicon doesn't indicate an icon is missing in any way, it simply shows a placeholder instead. It also doesn't extrapolate from sub-pages so `example.com` won't have a favicon even if `example.com/subpage` has one.
To prevent cross-page leaks we need to create/copy prefs and cachedStyles inside the background page context.
* storage.js is now used only in the background page
* messaging.js now contains less bg-specific methods and more common methods. Added saveStyleSafe, deleteStyleSafe which automatically invoke onRuntimeMessage of the current page or just handleUpdate/handleDelete when notify:false
* prefs.js with 'prefs' for background and UI pages: separate objects because a UI page may load before the background page and it can read prefs from localStorage/sync/defaults
* update state is shown in tooltips that fade out in 10 sec except for .update-problem and .can-update
* when updates are found a filtering option is revealed; when it's checked only entries with updates are shown; when all updates are installed the option automatically hides
* "Find styles" is a link so we make it one, just like in the popup.
* We have a dedicated global options UI so it makes no sense to subset only two of them on the manage page, moreover both options are unrelated to managing styles.
* Now that our own pages retrieve the styles directly via getStylesSafe the only 0.001% of cases where code:false would be needed (the browser is starting up with some of the tabs showing our built-in pages like editor or manage) is not worth optimizing for.
* According to CSS4 @document specification the entire URL must match. Stylish-for-Chrome implemented it incorrectly since the very beginning. We detect styles that abuse the bug by finding the sections that would have been applied by Stylish but not by us as we follow the spec. Additionally we'll check for invalid regexps.
