Add/Edit DMMAT var

[janineA]

After going down a few rabbit holes, decided to brute force copy addA2dVariable and insertA2DVariable and split into versions for ANALOG_NCAR and ANALOG_DMMAT. Deleting a DMMAT var now works. However, add and edit still need more tracing. Both are caught gracefully with a message box. Search for "DMMAT card not implemented yet" in AddA2DVariableComboDialog.cc and Document.cc to find where failures are preempted.

Breadcrumbs for future work:

• Edit DMMAT: AddA2dVariableComboDialog.cc line 267 in show(): call to name() causes code to crash. name() is a function of Variable, and I suspect that DMMAT cards are not inherited from Variable. Need to find equivalent call for DMMAT. Once that is fixed, there may be other things that need fixing through line 380.
• Add DMMAT: Document.cc line 2145 in addDSCVariable(): There are two different errors here:

1. If highlighting a DMMAT sensor when select "Add A2DVariable", on save a duplicate sample id error is thrown. When this happened for NCAR card, it was because on add, the code deletes all the existing vars and re-adds them plus the new var. But since A2DTEMP is not allowed to be deleted, get a duplicate A2DTEMP. Behaviour looks the same here so I suspect a var isn't being deleted correctly. May or may not be related: In order to be able to add a variable while a DMMAT sensor is highlighted (because there may not be any child variable available to highlight), I had to reset the pointer to the parent sensor to be the DMMAT card. See commit #4fcd112
2. If highlighting a variable under a DMMAT sensor when select "Add A2Dvariable", on save an out of sync error occurs. Haven't dug into this one at all yet...