support proxy request with custom querystring. like /test/urllib.test.js?__totoro_oid=_mWNt4XNRqA0WPuHAL4C&__totoro_lid=QmJSmrHA0jf2t5AiAL4B-node&__totoro_root_tgz=true
support ua.group
Merge pull request #81 from totorojs/fix-querystring

support proxy request with custom querystring.