added G-WAN (C++) with MySQL Benchmark

added G-WAN (C++) with MySQL http://gwan.com/

to test manually, start the server:
```shell
sudo ./gwan -d
```

to start the server in debug mode:
```shell
./gwan
```

to kill the server:
```shell
sudo ./gwan -k
```

available urls (Test type 1-6):
* http://127.0.0.1:8088/?json.cpp
* http://127.0.0.1:8088/?my.cpp
* http://127.0.0.1:8088/?my_multi.cpp&queries=250
* http://127.0.0.1:8088/?my_fortune.cpp
* http://127.0.0.1:8088/?my_update.cpp&queries=250
* http://127.0.0.1:8088/?plaintext.cpp