improve README
improve README

liviusATnetskope/second,sshling/tcpcopy,caosiyang/tcpcopy,left2right/tcpcopy,eliteYang/tcpcopy,liviusATnetskope/second,daodaoliang/tcpcopy,daodaoliang/tcpcopy,left2right/tcpcopy,ycaihua/tcpcopy,u20024804/tcpcopy,u20024804/tcpcopy,caosiyang/tcpcopy,sshling/tcpcopy,horryq/tcpcopy,wfxiang08/tcpcopy,eliteYang/tcpcopy,ycaihua/tcpcopy,wfxiang08/tcpcopy,horryq/tcpcopy