Cleaned up the comments and NodesToProcess flags enum in XmlSiteMapNodeProvider
Reverted node key logic to include the parent key because it broke the nested static node for dynamic node functionality.
Renamed SiteMapNodeParentMap to SiteMapNodeToParentRelation, as "map" twice in the same name is a bit confusing.
Moved the Order property into the SiteMapNodePositioningBase class and grouped it accordingly in the other files where it is implemented or overridden.
Added MvcSiteMapProvider_EnableSiteMapFileNestedDynamicNodeRecursion setting to enable V3 dynamic node recursion behavior, which called the nested dynamic node N+1 times (not sure why or how it could possibly be useful).