on branch serialization-with-dpath4

InteractiveDebugger.scala - removal of hidden nodes is broken.

The Infoset implementation of removeHiddenElements function modifies the infoset.

he Infoset implementation of toXML currently always skips and doesn't create XML for hidden elements.

The debugger needs to be able to create xml from the infoset either with or without the hidden elements, and without any modification to the infoset happening.

My guess is the right fix is to have toXML have a removeHidden flag to control whether or not the hidden elements are skipped past or not. Then the removeHiddenElements infoset operation can probably just go away, or rather, just not be used by the interactive debugger. (It might still be useful at the API level to trim off hidden elements before giving back the infoset for programatic consumption.)