Disabled touch input: always active gestures

[hius07]

Disabled touch input has become a popular feature. Let's enhance a bit:
-added separate actions "Touch input on", "Touch input off"
-added an option to make a gesture "always active" (even when the touch input is disabled)

This will help in cases like #10273.

I saw the @NiLuJe 's warning:

koreader/frontend/ui/widget/container/inputcontainer.lua

Lines 296 to 306 in b8af326

	-- NOTE: Monkey-patching InputContainer.onGesture allows us to effectively disable touch input,
	-- because barely any InputContainer subclasses implement onGesture, meaning they all inherit this one,
	-- making this specific method in this specific widget the only piece of code that handles the Gesture
	-- Events sent by GestureDetector.
	-- We would need to be slightly more creative if subclassed widgets did overload it in in any meaningful way[1].
	-- (i.e., use a broadcast Event, don't stop its propagation, and swap self.onGesture in every instance
	-- while still only swapping Input.onGesture once...).
	--
	-- [1] The most common implementation you'll see is a NOP for ReaderUI modules that defer gesture handling to ReaderUI.
	-- Notification also implements a simple one to dismiss notifications on any user input,
	-- which is something that doesn't impede our goal, which is why we don't need to deal with it.

but couldn't get any errors while testing, at least in a usecase "enable page turns with the bottom edge swipes with disabled touch input". Maybe I've missed something...

---

This change is 

[NiLuJe]

Not familiar with Dispatcher/Gestures, but this looks sound ;).

[NiLuJe]

I saw the @NiLuJe 's warning

That's more of a potential backend issue for potential future fancy widgets with funky gesture handling, the codebase still matches that assessment right now ;).

[yparitcher]

You might want to add touch_input_off to the list, as people might expect it to always work, like toggle

[yparitcher]

Sorry i meant touch_onput_on

[hius07]

Yes, I got it, a good idea.

[poire-z]

Not sure how often this is called, but if on all gesture, to make it possibly less expensive, you could factor out the first table lookup:

local ges = self.gestures[ges] 
return ges and (ges.toggle_touch_input or ges.touch_input_on or...