Implement object serialization

[andrewdalpino]

A common use case for objects in PHP is serialization and deserialization so their properties can be stored and then reloaded into memory with their class definition. This ticket is to implement serialization in the C Array extension such that when passed as an argument to serialize() or embedded deeper in the object-property tree stemming from the root object that is passed to serialize() the C Array buffer will be saved along with the other properties.

Example

$data = serialize($carray);

$carray = unserialize($data);