Basically:
* Use `extend` for class definitions
* Use `new` for object instantiations
That includes some minor code cleanups along the way:
* Updated `Widget`'s docs to make the semantics clearer.
* Removed `should_restrict_JIT` (it's been dead code since https://github.com/koreader/android-luajit-launcher/pull/283)
* Minor refactoring of LuaSettings/LuaData/LuaDefaults/DocSettings to behave (mostly, they are instantiated via `open` instead of `new`) like everything else and handle inheritance properly (i.e., DocSettings is now a proper LuaSettings subclass).
* Default to `WidgetContainer` instead of `InputContainer` for stuff that doesn't actually setup key/gesture events.
* Ditto for explicit `*Listener` only classes, make sure they're based on `EventListener` instead of something uselessly fancier.
* Unless absolutely necessary, do not store references in class objects, ever; only values. Instead, always store references in instances, to avoid both sneaky inheritance issues, and sneaky GC pinning of stale references.
* ReaderUI: Fix one such issue with its `active_widgets` array, with critical implications, as it essentially pinned *all* of ReaderUI's modules, including their reference to the `Document` instance (i.e., that was a big-ass leak).
* Terminal: Make sure the shell is killed on plugin teardown.
* InputText: Fix Home/End/Del physical keys to behave sensibly.
* InputContainer/WidgetContainer: If necessary, compute self.dimen at paintTo time (previously, only InputContainers did, which might have had something to do with random widgets unconcerned about input using it as a baseclass instead of WidgetContainer...).
* OverlapGroup: Compute self.dimen at *init* time, because for some reason it needs to do that, but do it directly in OverlapGroup instead of going through a weird WidgetContainer method that it was the sole user of.
* ReaderCropping: Under no circumstances should a Document instance member (here, self.bbox) risk being `nil`ed!
* Kobo: Minor code cleanups.
This helps jumping to page when ToC chapters are short
and the bookmap page rows narrow.
Also fix crash when invoking BookMap and PageBrowser
on a PicDocument (considered DocLess by Statistics).
- 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.
