Curl Client does not check if response code is 200 or 201

[piwi91]

I had an issue that I relied on your exceptions instead of the response of the CURL request. A response code of 400 couldn't be catched because there isn't an exception thrown if it occurs. An exception is only thrown when the result of the CURL request is false (https://github.com/onesky/api-library-php5/blob/master/src/Onesky/Api/Client.php#L360).
It is better to extend this check also with the CURL response code because only the expected response codes should be accepted.

[sc0rp10]

I totally agree that code >= 400 should raise exception