update guzzle to 3.7
bug #23 update guzzle to version 3.7 (juliendidier)

This PR was merged into the 1.0.x-dev branch.

Discussion
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update guzzle to version 3.7

You call ``GuzzleClient::setDefaultOption`` (https://github.com/sensiolabs/insight/blob/master/Sdk/Api.php#L54), which is implemented since guzzle 3.7

Commits
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d8f7617 update guzzle to 3.7