Android: Swith to pollOnce (#1358)
Android: Swith to pollOnce (#1358)

* Android: Switch to pollOnce

We don't use callbacks, so pollAll serves no purpose for us.
(It's just a wrapper around pollOnce that ensures every callback is
run).

* Document that some input events may report coordinates w/ subpixel precision.
koreader/koreader-base,Frenzie/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,koreader/koreader-base,NiLuJe/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,Frenzie/koreader-base,NiLuJe/koreader-base,Frenzie/koreader-base