Gnats 4629

Original Title: Supplied deleted when Exchange is deleted.
 (that's not actually happening).

Revised Title: Removing a Supply reference from an Exchange or Payback
 corrupts the Supply Type.

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Accounting/AccountingCBData.hpp
Accounting/Supply.hpp
Accounting/Supply.cpp
-------------------------------

Added AccountingCBData CallbackSubType:
  supply_role_changed

New callbacks generated from the following methods, using this call:
 callSupplyChangedCallbacks (AccountingCBData::supply_role_changed, ..);

 (1) void Supply::setStandaloneRole(); <<< NEW METHOD [Gnats 4629]
 (2) void Supply::setStandaloneRole(SupplyDemandType_t) throw (cwException);
 (3) void Supply::setExchangeInputRole   (Exchange*) throw (cwException);
 (4) void Supply::setExchangeBorrowRole  (Exchange*) throw (cwException);
 (5) void Supply::setExchangeDestRole    (Exchange*) throw (cwException);
 (6) void Supply::setExchangePaybackRole (Payback*)  throw (cwException);

-----------------------
Accounting/Exchange.hpp
Accounting/Exchange.cpp
-----------------------

When removing the _borrowSupply or _destSupply references
from the Exchange, those Supplies' Roles are now set back to "Stand Alone"
by the Supply method which doesn't effect the Supplies' Types.  Changes in:
  void Exchange::setBorrowSupply (Supply*, bool origDeleted)
  void Exchange::setDestSupply (Supply*, bool origDeleted)

=============

----------------------
Accounting/Payback.cpp
----------------------

Gnats 4629: Removing a Supply reference from an Exchange (OR PAYBACK) 
 corrupts the Supply Type.  [i.e. This bug APPLIES ALSO to the Payback 
 Supplies].

In method, void Payback::setPaybackSupply (Supply*, bool origDeleted)
 When releasing the previously referenced Supply, call the new version 
of the Supply::setStandaloneRole() which doesn't nail the Supply Type.

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