Split references into two overloads instead of default parameter
Minor changes to DataTag validation:comments&use decltype in template
Implemented template specialized version of extentsMatchPositions

extentsMatchPositions now has a special vector version for "extent" & "position" from SimpleTag instead of "extents" & "positions" from DataTag
Implemented use of new extentsMatchpositions version in SimpleTag

Also implemented further checks of units & extents & positions