a possible fix of #238

I fixed the reading of read_stdout pipe. We have to use `start_reading` to start the pipe or nothing will be piped.

![screen shot 2014-10-17 at 3 20 39 am](https://cloud.githubusercontent.com/assets/1690993/4677425/49200884-55e7-11e4-8cc7-e6bd269ed362.png)