changes on building (clean-up) and emulation code
changes on building (clean-up) and emulation code

cleaned up Makefile a bit and made emulation related
parts really conditional on a single flag (EMULATE_READER).

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