Create performance.md

doc/performance.md

+# RapidJSON Performance
+
+The old performance article for RapidJSON 0.1 is provided [here](https://code.google.com/p/rapidjson/wiki/Performance).
+
+This file will be updated with new version and better procedures.
+
+In the mean time, you may also refer to the following third-party benchmarks.
+
+## Third-party benchmarks
+
+* (Basic benchmarks for miscellaneous C++ JSON parsers and generators)[https://github.com/mloskot/json_benchmark] by Mateusz Loskot (Jun 2013)
+ * [casablanca](https://casablanca.codeplex.com/)
+ * [json_spirit](https://github.com/cierelabs/json_spirit)
+ * [jsoncpp](http://jsoncpp.sourceforge.net/)
+ * [libjson](http://sourceforge.net/projects/libjson/)
+ * [rapidjson](https://github.com/miloyip/rapidjson/)
+ * [QJsonDocument](http://qt-project.org/doc/qt-5.0/qtcore/qjsondocument.html)
+ 
+* [JSON Parser Benchmarking by Chad Austin](http://chadaustin.me/2013/01/json-parser-benchmarking/) (Jan 2013)
+ * [sajson](https://github.com/chadaustin/sajson)
+ * [rapidjson](https://github.com/miloyip/rapidjson/)
+ * [vjson](https://code.google.com/p/vjson/)
+ * [YAJL](http://lloyd.github.com/yajl/)
+ * [Jansson](http://www.digip.org/jansson/)