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.
* Rejig frontlight warmth API to more closely match the existing API, and, hopefully, clarify some of its quirks, and reduce boilerplate and duplicate code in platform implementations.
* Tweak Kindle:setDateTime to prefer using the platform's custom script, as in interacts better with the stock UI. And make the fallbacks handle old busybox versions better.
* Add Kindle PW5 support ;).
* Add warmth support to the Kindle platform.
* Random TextBoxWidget cleanups: make sure we immediately free destroyed instances.
* FrontLightWidget: Refactor to make it slightly less obnoxious to grok and update; i.e., separate layout from update, and properly separate brightness from warmth handling. Move to simpler widgets instead of reinventing the wheel.
* TextBoxWidgets: Implement `setText` to match TextWidget's API, as some callers may be using the two interchangeably (i.e., Button).
* NaturalLightWidget: Make sure we pass a string to InputText
* InputText: Add debug guards to catch bad callers not passing strings ;).
* QuickDictLookup, ImageViewer, NumberPicker: Smarter `update` that will re-use most of the widget's layout instead of re-instantiating all the things.
* SpinWidget/DoubleSpinWidget: The NumberPicker change above renders a hack to preserve alpha on these widgets almost unnecessary. Also fixed said hack to also apply to the center, value button.
* Button: Don't re-instantiate the frame in setText/setIcon when unnecessary (e.g., no change at all, or no layout change).
* Button: Add a refresh method that repaints and refreshes a *specific* Button (provided it's been painted once) all on its lonesome.
* ConfigDialog: Free everything that's going to be re-instatiated on update
* A few more post #7118 fixes:
* SkimTo: Always flag the chapter nav buttons as vsync
* Button: Fix the highlight on rounded buttons when vsync is enabled (e.g., it's now entirely visible, instead of showing a weird inverted corner glitch).
* Some more heuristic tweaks in Menu/TouchMenu/Button/IconButton
* ButtonTable: fix the annoying rounding issue I'd noticed in #7054 ;).
* Enable dithering in TextBoxWidget (e.g., in the Wikipedia full view). This involved moving the HW dithering align fixup to base, where it always ought to have been ;).
* Switch a few widgets that were using "partial" on close to "ui", or, more rarely, "flashui". The intent being to limit "partial" purely to the Reader, because it has a latency cost when mixed with other refreshes, which happens often enough in UI ;).
* Minor documentation tweaks around UIManager's `setDirty` to reflect that change.
* ReaderFooter: Force a footer repaint on resume if it is visible (otherwise, just update it).
* ReaderBookmark: In the same vein, don't repaint an invisible footer on bookmark count changes.
* Modernize jit syntax
It's built-in, no need for a require anymore.
* Flag Android should_restrict_JIT again
It's mildly helpful at putting off the inevitable.
(very, very, very, very mildly).
* Bump android-luajit-launcher
https://github.com/koreader/android-luajit-launcher/pull/281
to make koreader on Android more stable
and with these opt params:
```
require("jit.opt").start("sizemcode=64","maxmcode=64", "hotloop=10000")
```
The strategy here is that we only use precious mcode memory (jitting)
on deep loops like the several blitting methods in blitbuffer.lua and
the pixel-copying methods in mupdf.lua. So that a small amount of mcode
memory (64KB) allocated when koreader is launched in the android.lua
is enough for the program and it won't need to jit other parts of lua
code and thus won't allocate mcode memory any more which by our
observation will be harder and harder as we run koreader.
Without this fix, self.dimen is shared among all inputcontainers
intances, which breaks some of the UI rendering. All widget should
set/initialize their own self.dimen in self:init() method.
