crengine may now give us multiple authors (if multiple <dc:creator>
in epub metadata) separated by \n.
Deal with that where needed.
Limit the number of authors displayed in coverbrowser views.
Bumped base/crengine: multiple <dc:creator> + fix mobi images order
Bumped base: util.runInSubProcess(): give child its own process group
Speedup initialization (needs to be done only once, and avoid
saving current mode to sqlite each time) and reader-to-filebrowser
switch, by doing a single rendering (instead of 2 or 3 previously).
ListMenu: cache sidecar file parsing results (page/percent
completed) for the browsing session duration.
Fix "No choice available" when on last page and changing
to a display mode with less pages.
Made the onHold buttons table similar to the one of File browser.
Added "Purge .sdr" and "Delete" to these buttons.
Moved the purgeSettings and removeFileFromHistoryIfWanted
logic into filemanagerutil functions.
Stay on the same page when manipulating history (previously, we were
always put back on first page).
Really keep deleted files in history (unless setting says otherwise).
Show deleted files in grey or dimmed in classic History and all
CoverBrowser display modes.
* 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
