update readme to offer documentation alternative links
update readme to offer documentation alternative links

simplechen/cobarclient,wangcan2014/cobarclient,c3p0hz/cobarclient,alibaba/cobarclient,howepeng/cobarclient,matrix-stone/cobarclient,fengshao0907/cobarclient,IBYoung/cobarclient,elijah513/cobarclient,E312232595/cobarclient,yuzhu712/cobarclient,WilliamRen/cobarclient