[DON'T MERGE] [REVIEWER: AMC] Take new rapidjson

Unit tests run fine
See http://miloyip.github.io/rapidjson/classrapidjson_1_1_generic_value.html#ad22fdeac87ec6c370dd43075d3586811 the check is now `role_of_node_json != <blah blah>.MemberEnd()` (which suggests you might want to save of `<blah blah>` in a local variable.