[UX] Add Prev/Next page actions to GestureManager (#4570)
[UX] Add Prev/Next page actions to GestureManager (#4570)

c.f., https://www.mobileread.com/forums/showthread.php?t=315023
mihailim/koreader,koreader/koreader,pazos/koreader,houqp/koreader,poire-z/koreader,Frenzie/koreader,mwoz123/koreader,Hzj-jie/koreader,poire-z/koreader,NiLuJe/koreader,NiLuJe/koreader,koreader/koreader,Markismus/koreader,Frenzie/koreader