fine-tune offsets and panning
fine-tune offsets and panning

It's better to leave small margin at top, and remove margin when
panning left-right since we have margins anyway

chihyang/koreader,houqp/koreader,NiLuJe/koreader,houqp/koreader-base,koreader/koreader-base,frankyifei/koreader,koreader/koreader-base,apletnev/koreader-base,noname007/koreader,poire-z/koreader,koreader/koreader,Hzj-jie/koreader-base,koreader/koreader,apletnev/koreader-base,houqp/koreader-base,robert00s/koreader,apletnev/koreader,Frenzie/koreader,Hzj-jie/koreader-base,poire-z/koreader,frankyifei/koreader-base,NiLuJe/koreader-base,koreader/koreader-base,mihailim/koreader,apletnev/koreader-base,lgeek/koreader,Hzj-jie/koreader,ashhher3/koreader,NiLuJe/koreader-base,NiLuJe/koreader-base,houqp/koreader-base,Frenzie/koreader-base,Markismus/koreader,NickSavage/koreader,Frenzie/koreader,apletnev/koreader-base,houqp/koreader-base,Hzj-jie/koreader-base,ashang/koreader,Frenzie/koreader-base,NiLuJe/koreader-base,frankyifei/koreader-base,koreader/koreader-base,mwoz123/koreader,frankyifei/koreader-base,NiLuJe/koreader,pazos/koreader,Hzj-jie/koreader-base,Frenzie/koreader-base,frankyifei/koreader-base,chrox/koreader,Frenzie/koreader-base