Add an option to immediately run the web server after it's built

Hi,

To address #17, which in my case is caused by the slow bootstrapping of the web server, I come up with this work-around to run the web server immediately after it's built thus minimizing the effect of delayed port binding.

This, however, will not solve the race condition when the proxy tries to connect to a still-bootstrapping server, which is far more complicated... it only tries to start the application as early as possible so that hopefully when we switch to browser the server is already accepting connection.