* Fix the "Enable debug logging" checkbox so that it properly disables "Enable verbose debug logging" when it gets disabled
* Avoid asking ImageWidget for alpha-blending when it's not useful
* Make ImageWidget's alpha-blending code-path double-check that alpha-blending actually is needed, and avoid it if possible
* In the same vein, only do alpha-blending in textboxwidget when absolutely necessary
* Prefer color constants over the gray() method, ensuring that they're part of the eInk palette
Depends on https://github.com/koreader/koreader-base/pull/853Fix#4774
Mostly all that have a close button at top right, that may
be hard to reach or hit for some people: TOC, Bookmarks, History,
KeyValuePage (Book information, Statistics...), Book status...
Added full refresh on diagonal swipe where it was missing.
CoverMenu: removed onSwipe override, as it had become the same as
Menu a few months ago.
* [device][kindle4] add fake event to kindle4
* modify focusmanager to allow for more complex layout
The focusmanager now naviguate the layout by avoiding nil value
instead of relying on table lenght. It should be completely backward
compatible
* add Dpad naviguation to the touchmenu
* fix crash because virtualkeyboard on non touch device
the kindle4NT has no keyboard nor touch, the fix open the virtual
keyboard so koreader dont crash but it's not useable
* Enable device with keys to use the touchmenu
* Don't get stuck in reader progress statistics plugin
* [underlinecontainer] Fix and remove unused function
References #1898.
* Prevent open screensaver more than one in the same time
* Add option to enable/disable background in message screensaver
* fallback to random images if this book cover is excluded feature + fix Disabled (leave screen/page as it is)
* Autostretch disable by default, more fallback options, leave screen as it is
