Parsing of advanced path not working.

`func testAdvancedPath() {
        let result = PathParser.parse(path: "$.array[?(@.id==5)]")
        XCTAssertNotNil(result)
}`

=> This doesn't return a valid path, json to test with is following, check with http://jsonpath.com:

`{
  "array": [
    {
      "id": 4
    },
    {
      "id": 5
    }
  ]
}`