ssb: Enough plumbing that if a blob is received, we will try to load the image again.

core/core.js

@@ -693,6 +693,10 @@ ssb.addEventListener('message', function () {
 	broadcastEvent('onMessage', [...arguments]);
 });
 
+ssb.addEventListener('blob', function () {
+	broadcastEvent('onBlob', [...arguments]);
+});
+
 ssb.addEventListener('broadcasts', function () {
 	broadcastEvent('onBroadcastsChanged', []);
 });