more pretty arguments handling. print default values in usage
more pretty arguments handling. print default values in usage

mentesc/slowhttptest,tectronics/slowhttptest,0x37N0w4N/slowhttptest,jengyic/slowhttptest,mfazliazran/slowhttptest,Chigirin/slowhttptest,0x37N0w4N/slowhttptest,jengyic/slowhttptest,a12689851/slowhttptest,yeahdongcn/slowhttptest,yeahdongcn/slowhttptest,mfazliazran/slowhttptest,a12689851/slowhttptest,mentesc/slowhttptest,tectronics/slowhttptest,jack-ju/slowhttptest,Chigirin/slowhttptest,jack-ju/slowhttptest