Make iodocs module friendly

Make iodocs module friendly, so it can be installed as a dependency: index.js created, so a config file can be injected. 

After that, this is possible:

```
var iodocs = require('iodocs')({
    "title" : "I/O Docs - http://github.com/mashery/iodocs",
    "address": "0.0.0.0",
    "port" : 5000,
    "apiConfigDir" : "../../docs",
    "debug" : false,
    "sessionSecret" : "12345",
    "basicAuth" : {
      "username" : "",
      "password" : ""
    },
    "redis" : {
      "host" : "localhost",
      "port" : 6379,
      "password" : "",
      "database" : "0"
    }
  }
);
```