Throw Gaze errors

If Gaze errors for any reason, the pipeline is drawn to a halt and no error is propagated. (Discovering this silent error took me many hours!)

This is because [the Gaze `EventEmitter`](https://github.com/plumberjs/plumber-glob/blob/ca3f538edd00ce7b4364eb83177981146544eea6/index.js#L38) has a default event handler for `error` events, which catches the error. Ideally you would just remove the default event handler with `gaze.removeListener('error')` so that errors are thrown, however there is an issue in the most recent version of Gaze that breaks this functionality: https://github.com/shama/gaze/issues/128. The issue is fixed but not published.

Either we wait until the fix to Gaze is published (it's been a long time already) or we reference a forked version with the patch applied. Thoughts?

Also, is removing the event listener the correct fix to plumber-glob, or should we instead plug the error event into the observable sequence? Am I correct to believe the former would lead to an uncaught exception, whereas the latter would propagate the error through the sequence (eventually leading to an uncaught exception, maybe)?

Let me know the answer to these two questions and I'll update this PR so we can merge it!