Snapshot Object "Relationships" maintained for Exported Objects and Scenarios
Bug Number: n/a
Release notes (y/n): Yes
For Release Nums: 6.3

Exporting and re-importing Snapshot Objects had not previously been fully 
supported in RiverWare: the associations of the Snapshot Object's slots 
with the original slots from which the snapshot was made had not been 
retained.

This was also a problem for the current Scenario enhancements which 
include a special automatically generated Snapshot Object for the 
Scenario's outputs. (New scenario files contain a serialized Snapshot
Object if the scenario had been run).

Both of these limitations have been addressed.  In the case of both
exported objects and saved scenarios, the snapshot objects "relationships"
are written out after the objects standard "entity" values.  This results
in "snapshotOf" Tcl commands to be included in the serialization.  When 
loading these objects or scenarios, a call to the Snapshot Manager's
"resolveCachedSlots" method finalizes the recreation of the "snapshotOf"
relationships.

Changes to Sim/SimWS.cpp:
  (1) In SimWorkspace::dumpObjectFile(const QString& filename,
                                      const std::set<SimObj*>&) const 
  ... after iterating through the given SimObj set to call 
  SimObj::dumpEnt(), a second iteration calls SimObj::dumpRel()
  only on Snapshot Objects within that list.
  
  (2) In these two methods:
    SimWorkspace::loadObjectFile(const rwFile& ..)
    SimWorkspace::loadScenarioFile(const rwFile& ..)
  ... snapShotMgr->resolveCachedSlots() is called as a final step.

Changes to Sim/Scenario.cpp:
  In Scenario::dump(cwostream &os) const
  ... If the Scenario has an associated Scenario Output Snapshot Object,
  dump that objects "relationships" as well as its "entities":
  
     snapObj->dumpEnt(os);
     snapObj->dumpRel(os);   // <<< ADDED
     
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