Drupyx implementation and test coverage

php:
- serialize: this package uses original PHP unit tests, adapted to Python
  - implementation
    - serialize: all types. TODO: _sleep, circular references
    - unserialize: array (separates list/dict), bool, int, none, string. TODO: float, object, _wakeup, circular references
  - tests
    - 001.phpt - basic serialize: serialize: 18/21 implemented, 18 passing; unserialize: 0/1 implemented
    - 002.phpt - basic unserialize: 4/9 implemented, 4 passing