If JobEngine is active, then use it to copy/rez attachments for an avatar entering the scene that isn't initially logging on.  This will execute tasks consecutively rather than concurrently.

This has two aims
1) Reduce initial teleport failures when a foreign Hypergrid user enters a region by not holding up the teleport for attachment rez (this can be particularly costly when HG gets all assets in the object graph.
2) Reduce server load that may impact other simulator activities.
This complements existing JobEngine options that perform initial login attachment rez and appearance send in consecutive tasks.
Start JobEngine by default in simulator for now.