Also tweak ReaderHighlight:onHoldRelease() to avoid
doing its stuff when onHold() is clearing highlight
(previous CheckButton was closing/clearing on hold
release, new TitleBar close button does that on hold).
- Fix hold callback name
- Add options to handle long titles (truncated by default):
"title_multines" and "title_shrink_font_to_fit" (allowing
setTitle() with them makes the code a bit more complex).
- Add options to set bottom line color and horizontal padding.
- Use an added close.svg (based on exit.svg, tweaked to have
similar size and baseline as other icons) for close button.
IconButton:
- handle hold/hold_release similar to Button.
- new option allow_flash to allow disabling flashing.
- Book map: shows a map of content, including TOC,
boomarks, read pages, non-linear flows...
- Page browser: shows thumbnails of pages.
- ReaderThumbnail: new Reader module that provides
a service for generating thumbnails of book pages.
It makes available these 2 new fullscreen widgets.
- ReaderBookmark, ReaderLink, Statistics: add methods
to return new views of bookmarks, previous locations
and read pages, that are needed by BookMapWidget.
- ReaderToc: compute TOC max_depth.
- ReaderBookmark, ReaderHighlight: send events on
bookmark add/update/remove so thumbnails of the
pages impacted can be trashed.
Existing widgets building their own title bar with help
of CloseButton should progressively be updated to use
this, for clarity, consistency, and less code duplication.
On folders, instead of "5 items", show "2 dirs 3 files"
separately (using symbols for "dirs" and "files").
Also fix: if files filtering is enabled, PathChooser did
show the full number of files in subfolders, instead
of the number of filtered files.
When TextViewer is showing up, it causes screen refresh of the rectangle from the upper left corner of the screen (0,0) till the lower right corner of the TextViewer window (the result of `combine`).
So when the TextViewer is not full-screen, left and upper parts of the screen are refreshed.
This unpleasent screen flashing can be seen, for exampe, when showing book description from the Book information page, or when calling the clipboard (long-press on the text input box).
Let's show the TextViewer in a usual way, as (almost) all other widgets do.
In response to the comment by @ilyats on Weblate:
> Text appears in code twice, as menu item and as dialog button label. Ideally, translations should be different.
Move Default and extra buttons above Cancel/OK.
Default values shown in the default button.
Precisions can be set for both values separately.
Minor geometry fix for consistence with SpinWidget.
