Added fix for future UIWebView implementation. Now checks if the proxy responds to a selector.
Added fix for future UIWebView implementation. Now checks if the proxy responds to a selector.

TimorCan/NJKWebViewProgress,vvw/NJKWebViewProgress,linxiaoguo/NJKWebViewProgress,liuruxian/NJKWebViewProgress,zhaoguohui/NJKWebViewProgress,jianwoo/NJKWebViewProgress,zhouwude/NJKWebViewProgress,ninjinkun/NJKWebViewProgress,hanhailong/NJKWebViewProgress,phaibin/NJKWebViewProgress,XuXiaoJunChina/NJKWebViewProgress,AbooJan/NJKWebViewProgress,Suninus/NJKWebViewProgress,bboyesc/NJKWebViewProgress,xb123456456/NJKWebViewProgress