Two small cleanups and the offer->ACCOUNT->offer fix

1) When pathfinding, don't output a redundant account node.
This node serves no purpose because expandPath adds the node anyway. It's just a waste of bandwidth and space.

2) Cleanup some stray formatting
Obviously-correct cleanup.

3) Fix offer->ACCOUNT->offer

CAUTION: The third change affects transaction processing and requires planning and coordination in deployment. It should probably be combined with other transaction processing changes. (tefDST_TAG_NEEDED, for example.)
I guess I don't understand the question. At this point in the code, we're just adding an order book. The path might end on another order book or on an account. If we don't add order books to paths, we'll never find paths containing order books. At that point, the path (thought no complete) ends with an order book, until we add something else to it.