Added "use_arrays" option to control $assoc argument of json_decode()

This improves commit b2037aff71768e6ecb2e70b9b31768b562d00aac
Removed outdated and broken ZendhttpclientAdapter
Fixed Record::toArray() to recurse properly on arrays of objects

Previously, arrays of stdClass weren't converted to arrays of
associative arrays
Optimized performance of Record::toArray()