Making public virtual method "DynamoModel.ShutDown" as non-virtual
Making public virtual method "DynamoModel.ShutDown" as non-virtual
Refactored various shutdown related DynamoViewModel methods
Fix crash when invoking Form.ByLoftCrossSections with null input.

Conflicts:
	src/Libraries/Revit/RevitNodes/Elements/Form.cs
Merge pull request #2458 from Benglin/master

Fix crash when invoking Form.ByLoftCrossSections with null input.
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into ShutdownSequence
Conditionally call "OnRequestClose" if "CloseDynamoView" is "true"
Disabled "heartbeatThread.Join" statement to avoid deadlock
Update the geometry binaries
Merge pull request #2465 from Benglin/master

Disabled "heartbeatThread.Join" statement to avoid deadlock
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into ShutdownSequence
Making "DynamoModel.ShutDown" throw exception if called twice
Merge pull request #2464 from Randy-Ma/master

Update the geometry binaries
Added checks to handle reentrant of "PerformShutdownSequence"
Moved "IdlePromise.ClearPromises/Shutdown" calls out of "DynamoView_Closing"
Change vendor ID to ADSK.
Update vendor ID for msi installed addins.
Fix cherry-picking conflicts
Merge pull request #2474 from pboyer/TesselFixMaster

Cherry-pick RevitVisualizationManger improvements to Master
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into ShutdownSequence