Add plugin-specific sections in settings.json

Settings for specific plugins are written down as below:
{
  ...
  "ep_pluginname": {
    "foo":"bar"
  }
  ...
}

src/node/utils/Settings.js

@@ -135,7 +135,8 @@ for(var i in settings)
   }
 
   //we know this setting, so we overwrite it
-  if(exports[i] !== undefined)
+  //or it's a settings hash, specific to a plugin
+  if(exports[i] !== undefined || i.indexOf('ep_')==0)
   {
     exports[i] = settings[i];
   }