HttpClient breaks querystrings containing encoded = and &

[bmjames]

The process of decoding and re-encoding the querystring does not correctly handle encoded occurrences of = and &, and leaves them unencoded in the resulting URI.

For example,

client.get("foo?bar=baz%3Dqux%26quux")

will result in the client making this request:

GET /foo?bar=baz=qux&quux HTTP/1.1

It should be this:

GET /foo?bar=baz%3Dqux%26quux HTTP/1.1