Added "LegacyAssembly" property to "DSCoreNodesUI.DummyNode"
Introduced "DummyNode.Nature" to differentiate Obsolete and Unresolved nodes
Renamed "CreateDummyNodeForFunction" to "CreateUnresolvedFunctionNode"
Introduced "MigrationManager.CreateMissingNode" method, added test case
Redirected relevant callers to call "CreateMissingNode" instead
Improved DummyNode to tell a Deprecated node from an Unresolved one
"Bad nodes" are now turned into "Dummy nodes" during load time
Updated "MissingNode.png" with one that is designed in-house
Updated "Image.Stretch" to "Stretch.None" to avoid stretching
Merge pull request #1419 from Benglin/MAGN-2469

Fix Revit nodes being shown as "Deprecated" on standalone