Reworking management of Slot Dialogs, no longer via Open Object Dialogs [1]
Bug Number: n/a
Release notes (y/n): no
For Release Nums: 7.2

Open Slot Dialogs had been managed in an astonishingly complex way using 
BaseRWDlg Parent/Child Dialog relationships, using multiple phases of 
interactions involving the OpenObjectDlg, each of the five Slot Dialog 
classes, and a really messed up "SlotDialogManager" class (which was really 
just a lot of goop connected to the BaseRWDlg class).

This commit is the third try to separate out the management of Slot Dialogs.
Prior attempts involved attempting to make the pieces of this mechianism 
within the OpenObjectDlg _static_, and them moving it out from that class.
I ran into a lot of problems with that.

This commit represents the initial work (basically functional) to manage 
SlotDialogs from the Q3GUI/Workspace class, essentially in parallel with 
(i.e. in basically the same way as) the management of OpenObject dialogs.

The current changes are fairly broad, because I had to back off of managing 
Slot Dialogs as BaseRWDlg instances.  But the fundamental mechanism is in 
these methods:

  QMainWindow* Workspace::openSlot (Slot* slotPtr, bool inViewer /*=true*/)
  QMainWindow* Workspace::createOpenSlotDlg (Slot* slotPtr)
  void Workspace::openSlotDlgDestroyed (QObject* qobj)

Slot Dialogs are supported using these five classes:

  Q3GUI/SlotQtDlg
  Q3GUI/ListSlotDlg
  Q3GUI/ScalarSlotDlg
  Q3GUI/StatTableSlotDlg
  QtUtils/MassBalSummaryDlg  (NOT a BaseRWDlg).

---