Let's use reference_date_method_id on Trade Model Paths.

* Code clean up
* Remove hardcoded ledger to pick date
* Add code to defined source section when none is defined

* Fix for special case where purchase packing list is root.

* Use getSourceAssetPriceCurrency
* Do not expand if no SourceAssetPrice

We need to be able to see the future without auto planned orders, else how are we going to update them?