[ADD] Check UTF8 string and covert to UTF8
[ADD] Check UTF8 string and covert to UTF8

jiangzhonghui/egret-core,jarvys/egret-hacking,wl3780/egret-core,SmallAiTT/egret-core,SamuelGavin/egret-core,Lanfei/egret-core,unsilence/egret-core,unsilence/egret-core,Lanfei/egret-core,wisdomsword/egret-core,SamuelGavin/egret-core,wl3780/egret-core,jiangzhonghui/egret-core,SmallAiTT/egret-core,jarvys/egret-hacking,wisdomsword/egret-core