support for percentage copying
support for percentage copying

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