prepare changelog for v0.16
prepare changelog for v0.16

binsee/wechaty,Chatie/wechaty,binsee/wechaty,mukaiu/wechaty,zixia/wechaty,mukaiu/wechaty,mukaiu/wechaty,wechaty/wechaty,Chatie/wechaty,wechaty/wechaty,lijiarui/wechaty,binsee/wechaty,wechaty/wechaty,zixia/wechaty,lijiarui/wechaty,Chatie/wechaty