* frontlight on kobo: a few fixes
Rewritten to not update NickelConf on every change, and never
if KOBO_SYNC_BRIGHTNESS_WITH_NICKEL = false.
Reintroduce global settings frontlight_intensity and
is_frontlight_on to keep level and state across koreader
sessions.
Fix a few of the remaining issues on kobo light.
Ensure settings are saved when rebooting/powering off from
File browser.
* Ensure untoggle works when starting with light off
* fixes#2898 (prevents accidentally triggering reboot or poweroff)
Add ConfirmBox before reboot/power off
* increases clarity by preventing second page
* add "sleep" menu entry
* Add exit menu hold callback
Base bumped.
Previsouly, parts of document in <p style="font-family: serif">
would be rendered with the first font set, and would not
follow change of font (unline other texts without styles).
That was observable with Embedded Styles set to On, but is even
more noticiable with the new Embedded Fonts setting set to off.
Just under the existing "Embedded Styles". Support for this
was already there in crengine, and interfacing is similar to
what is done with Embedded Styles.
* Put back fl_min=0 as it is for all other devices (the idea
fl_min should be 1 and toggling managed some other way is
not implemented in current code).
* Fix a few frontlightwidget issues
For people who set autoremove_deleted_items_from_history to true,
file is removed from history when Deleted or 'Purge .sdr'. This also
update lastfile to the new top in history if needed.
So an image file can have a cover in coverbrowser's display.
It also allows for an alternative viewer (ImageViewer widget)
when holding on file / View full size cover.
* CoverBrowser plugin: alt views for File Browser and History
* Added Prune cache and Compact cache menu actions
* Support for book descriptions, and settings stored in db
lfs.dir will crash rather than return nil if directory doesn't exist
Proper fix for 9f5e446701 which is nothing but a workaround. However, I do think creating more of those data dirs automatically is more user-friendly because otherwise Android users will have to look it up or guess.