Added match expander that allows to match nullable @json@ objects

[norberttech]

This is continuation of #101 originally created by @partikus that introduce extremely flexible match expander. It also closes #133

All examples will return true:

(new MatcherFactory())->match(
  '{"image":null}',
  '{"image":"@null@||@[email protected]({\"url\":\"@[email protected]()\"})"}'
);

(new MatcherFactory())->match(
  '{"image":{"url":"http://image.com"}}',
  '{"image":"@null@||@[email protected]({\"url\":\"@[email protected]()\"})"}'
);

(new MatcherFactory())->match(
  '{"image":{"url":"http://image.com"}}',
  '{"image":"@[email protected](optional(), match({\"url\":\"@[email protected]()\"}) )"}'
);