Fix for selection box dragged out of canvas.

Fix for User gets stuck in selection mode when selection box is dragged
out of canvas.
Toggle and highlight assemblies that are node libraries
Fixes MAGN-4817. Simplified convesion from a Autodesk.DesignScript.Arc to a Revit Arc, using 3 point constructor.
Deserialize/serialize node library names
Update installed packages UI to represent masked packages
Merge branch 'master' into MAGN-4817
Added test case for tilted arc
Fix mistake in HasAuthenticator
Various minor fixes
Removed "NodeViewModel.OldValue" property
Removed "EngineController.GetStringValue", it's not referenced
Fix MAGN-5082 Dynamo does not notice if a change (delete or move) has occurred to an import instance
Fix for Selection box dragged out of canvas

Commented the mouse leave event on WorkspaceView.
Fix for selection box dragged outside the canvas

Removed the mouse leave event on Workspace view.
Captured the mouse event on LeftButtonDown and  released the mouse
capture on LeftButtonUp. This will ensure that selection is not lost
even when the mouse is dragged outside the canvas.
Handled the mouse lost focus event on DragCanvas. This will ensure that
selection is removed if the mouse is released outside the canvas.
First pass
UI cleanup of search
Various performance improvements/tweaks
Misc cleanup
Fixed deadlock in Watch3DView.VisualizationManagerRenderComplete
Added Test Cases those were generated from Defects.