Release 0.99.2

• Included workaround for a C++11 issue in GCC 4.8, contributed by Alex Merry

• Fixed operator== so that json() == json(json::object())

• Fixed issue with json assignment to initializer list

• Fixed issue with assignment to empty json object with multiple keys, e.g.

  json val;
  val["key1"]["key2"] = 1;