duplicate query keys not possible with GET requests

[GregorioDiStefano]

Firstly, great package! Thanks for making this.

It seems that it's not possible to create a GET request, with parameters such as "http://localhost/file?tags=a&tags=b" since Params is a map.

See here:

ro := &RequestOptions{
	Params: map[string]string{"Hello": "Goodbye"},
}
Get("http://httpbin.org/get?Hello=World", ro)

would you accept a pull request to fix this?

Thanks, Greg

[levigross]

Sure -- I have been meaning to change this API

[luotianzhu]

post same param name is not work ,like post htt://a.com body a[]=1 a[]=2 please help me