update readme
update readme

mc7246/WeiXinMPSDK,jiehanlin/WeiXinMPSDK,mc7246/WeiXinMPSDK,jiehanlin/WeiXinMPSDK,down4u/WeiXinMPSDK,wanddy/WeiXinMPSDK,JeffreySu/WeiXinMPSDK,wanddy/WeiXinMPSDK,jiehanlin/WeiXinMPSDK,lishewen/WeiXinMPSDK,mc7246/WeiXinMPSDK,wanddy/WeiXinMPSDK,JeffreySu/WeiXinMPSDK,down4u/WeiXinMPSDK,lishewen/WeiXinMPSDK,lishewen/WeiXinMPSDK,JeffreySu/WeiXinMPSDK,down4u/WeiXinMPSDK