Implemented: Setting option CURLOPT_READFUNCTION.
Implemented: Set cURL option  CURLOPT_CUSTOMREQUEST sets HTTP method.
Implemented: Adds test for CURLOPT_READFUNCTION curl option setter.
Fixed: Adds missing HTTP methods.
Implemented: Adds a more functional test for Guzzle posts.
Fixed: Calls a callable using call_user_func_array for 5.3 compatibility.
Fixed: Calls assertions on correct test class.
Merge pull request #46 from php-vcr/guzzle-post-fix

Guzzle POST fix