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.
* Revamped most actions that require an internet connection to a new/fixed backend that allows forwarding the initial action and running it automatically once connected. (i.e., it'll allow you to set "Action when Wi-Fi is off" to "turn_on", and whatch stuff connect and do what you wanted automatically without having to re-click anywhere instead of showing you a Wi-Fi prompt and then not doing anything without any other feedback).
* Speaking of, fixed the "turn_on" beforeWifi action to, well, actually work. It's no longer marked as experimental.
* Consistently use "Wi-Fi" everywhere.
* On Kobo/Cervantes/Sony, implemented a "Kill Wi-Fi connection when inactive" system that will automatically disconnect from Wi-Fi after sustained *network* inactivity (i.e., you can keep reading, it'll eventually turn off on its own). This should be smart and flexible enough not to murder Wi-Fi while you need it, while still not keeping it uselessly on and murdering your battery.
(i.e., enable that + turn Wi-Fi on when off and enjoy never having to bother about Wi-Fi ever again).
* Made sending `NetworkConnected` / `NetworkDisconnected` events consistent (they were only being sent... sometimes, which made relying on 'em somewhat problematic).
* restoreWifiAsync is now only run when really needed (i.e., we no longer stomp on an existing working connection just for the hell of it).
* We no longer attempt to kill a bogus non-existent Wi-Fi connection when going to suspend, we only do it when it's actually needed.
* Every method of enabling Wi-Fi will now properly tear down Wi-Fi on failure, instead of leaving it in an undefined state.
* Fixed an issue in the fancy crash screen on Kobo/reMarkable that could sometime lead to the log excerpt being missing.
* Worked-around a number of sneaky issues related to low-level Wi-Fi/DHCP/DNS handling on Kobo (see the lengthy comments [below](https://github.com/koreader/koreader/pull/6424#issuecomment-663881059) for details). Fix#6421
Incidentally, this should also fix the inconsistencies experienced re: Wi-Fi behavior in Nickel when toggling between KOReader and Nickel (use NM/KFMon, and run a current FW for best results).
* For developers, this involves various cleanups around NetworkMgr and NetworkListener. Documentation is in-line, above the concerned functions.
This commit standardizes the various todos around the code a bit in a manner recognized by LDoc.
Besides drawing more attention by being displayed in the developer docs, they're also extractable with LDoc on the command line:
```sh
ldoc --tags todo,fixme *.lua
```
However, whether that particular usage offers any advantage over other search tools is questionable at best.
* and some random beautification
TouchMenu: added options to menu items with the following defaults:
keep_menu_open = false
hold_keep_menu_open = true
So, default for Tap callback is to close menu, and for Hold callback
to keep menu open.
In both cases, provide the TouchMenu instance as the 1st argument to
the callback functions (instead of a refresh_menu_func I added in #3941)
so the callback can do more things, like closing, refreshing,
changing menu items text and re-ordering...
ReaderZooming: show symbol for default (like it was done for
ReaderFont, ReaderHyphenation...)
TextEditor plugin: update the previously opened files list in real
time, so the menu can be kept open and used as the TextEditor main
interface.
SSH plugin: keep menu open and update the Start/Stop state in real time
ReadTimer plugin: tried to do what feels right (but I don't use it)
Also remove forgotten cp in the move/paste file code
* plugin loader(feat): support loading plugins from user defined directories
Extra plugin lookup paths can be set in global reader setting via key
`extra_plugin_paths`. Value of the key can either be a string or an array
of strings.
* build(fix): also purge non-exist plugins on build
* plugin: migrate debug plugin to menu sorter
MenuSorter: forgot to add plugin style change
MenuSorter: worked out the final quirks
* Menu always compressed into tables without missing indexes for ipairs compatibility
* Orphans attached
* Separators no longer count as items
