Adds the CountNodes() expansion method to IFileDBDocument. It iterates over the Node structure starting with the Roots to count all nodes and adds 1 (for the "Content" node). For simplification of the calculation, Tags now have a method to recursively count their children.
Restructured IFileDBWriter and its implementations a bit to split up the writing of the tag section and the offsets, so that v3 can write the node count in between.
Adds the CountNodes() expansion method to IFileDBDocument. It iterates over the Node structure starting with the Roots to count all nodes and adds 1 (for the "Content" node). For simplification of the calculation, Tags now have a method to recursively count their children.
Restructured IFileDBWriter and its implementations a bit to split up the writing of the tag section and the offsets, so that v3 can write the node count in between.
Updated FileDB v3 Unit Test.