Dashboard from config

Hello.

These changes allow you to define your dashboards and jobs in one file (config/config.json). 

In the future I want to be able to configure dashboards from the browser instead of hacking the code. This is the first step in this direction. 

Separation of job implementation from it's configuration allows better code reuse - see example of twitter job in config.json. 

To see it working check [http://localhost:3030/sample-dyn](http://localhost:3030/sample-dyn)