Added fix for duplicate node fields found
Added fix for duplicate node fields found

* Added fix for duplicate node fields found while iterating through base fields; on 2019.3 using .Net 20 getting the fields of the node type will return all base type fields as well. This results in the iteration up through the base classes and adding their instance fields resulting in duplicates which causes errors on node creation when assigning port information.

Siccity/UnityNodeEditorCore