Java: better ping message to allow quick test

this is improvement of #123

``` http://<servername>/<foldername>/proxy.jsp?ping ```

then it will return json message with 200 code if web server is set up correctly with configuration and log file.

``` { "Proxy Version": 1.1 Beta, "Java Version": 1.7.0_45, "Configuration File": OK, "Log File": OK} ```

![3](https://cloud.githubusercontent.com/assets/5265339/3476096/b84adb44-02f9-11e4-8947-0a5b3116f70a.PNG)