Errors unhandled in ORM

[alexanderlperez]

Another dev I'm working with ended up hunting for half-an-hour looking for a reason why an activity wasn't triggering as expected, turns out there was a typo in the field.

However, definitely something avoidable if errors were accessible from the mongoose hooks. Right now they end up unhandled:

stream-node-orm/src/backends/mongoose.js

Lines 104 to 108 in 14ca95f

	doc.populate(paths, function(err, docP) {
	if (docP.wasNew) {
	stream.FeedManager.activityCreated(docP);
	}
	});

[dwightgunning]

Thanks for the report.