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.
Make it a real Document property, updated at init & toggle time.
Also, simplify a bunch of redundant nested lookups in ReaderView
(self.ui.view is self, self.ui.document is self.document).
It can happen in perfectly sane contexts.
CReDocument: Don't destroy internal engine data when Document just
decreased the refcount (as opposed to actually tore down the document
userdata if it were the last ref).
PdfDocument: Only write edited documents if the Doc instance was torn
down.
PicDocument: Silence some DocumentRegistry related warnings
Avoids a use-after-free in mupdf.scaleBlitBuffer
Fixkoreader/koreader-base#821
Thanks for the hint, @poire-z ;).
* As @poire-z suggested, the original unscaled bb should probably be free'd.
* Allow for colored rendering
Available with all engines (CRE, PDF, Images).
Needs to manually add setting: "color_rendering" = true
* Disable color for djvudocument
* Use Screen:isColorEnabled()
* Bump base
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.
