Error callback function

[torshid]

Hi,
Just a small suggestion here: specifying a custom error callback function in the config.
Something like that (in the twitterFetcher.js):

if (data.body === undefined) {
 if (customErrorCallbackFunction !== null) {
  customErrorCallbackFunction();
 }
 //also check inProgress
 return;
} 

Instead of:

if (data.body === undefined) {
 return;
} 

It would be even better to have informations about the error.

Thank you and good job by the way.