[ADD/WIP] Push all the Janet changes

This is still unstable(and I still need to design/document the exposed
API)! Do(n't) go and use it!

src/Routes/Transactions.c

@@ -34,6 +34,10 @@ RouteHead(RouteTxns, arr, argp)
     for (i = 0; i < ArraySize(events); i++)
     {
         HashMap *event = JsonValueAsObject(ArrayGet(events, i));
+        if (ExtensionPushEvent(args->data->exts, event))
+        {
+            continue;
+        }
         ParseeEventHandler(args->data, event);
     }