If a cookie already exists and the server asks to set it again with a null value, the cookie must be deleted.
Guarding against the case of a cookie with the same name but with different attributes like domain, path, etc...
If-Modified-Since should set only when server have return Last Modified in a response.
Implement cookie path matching algo described in RFC6265 s5.1.4
Merge pull request #548 from scalopus/RevalidationWithoutLastModified

If-Modified-Since should set only when server have return Last Modified ...
Updating MockPlugin to throw an exception if queue is empty
Use request QueryString to compose OAuth params

The Oauth "string to sign" includes the query string parameters,
together with the OAuth parameters. Guzzle uses a QueryString instance
to combine the two. However, it was incorrectly using the default
aggregator, instead of the actual aggregator used by the QueryString
that's part of the request.

This change uses the QueryString from the request to serialise the
parameters to be signed. This will affect the aggregation of the Oauth
parameters as well -- however aggregation should never occur for these
because there is only one value for each key.
fix php version issue #14 from ErrorResponsePlugin
Sort using using lexicographical byte value ordering

See 9.1.1 in http://oauth.net/core/1.0/
> Parameters are sorted by name, using lexicographical byte value ordering.

This is already fixed in Guzzle4, but a patch to Guzzle3 would be appreciated, as I encountered this bug, in my case when posting an array with more then 9 items.
Also see https://github.com/guzzle/guzzle/issues/558 and #4
Merge pull request #23 from barryvdh/patch-1

Sort using using lexicographical byte value ordering