First progress in getting the new visualization manager working.

New visualization manager files and move IDrawable.
Merge branch 'master' into VizManager
Remove dynIDrawable again.
Get RenderDescription back. Add Visualization class.
Move the ASM vis manager into core. Fix mesh redraw issue.
Avoid circular update.
Remove this stupid warning.
Hooking to watch 3d nodes the old way.
Progress.
Don't update visualizations at node loading and node deletion.
Make visualization manager property virtual.
Merge branch 'master' into VizManager
Add the visualization manager tests file.
Visualization manager tests. Ensure visual deletion on error.
Testing for visualizations cleanup on connector drop. Fix for zero length asm lines.
Use disconnect instead of delete to remove connector in test.
Add a Helix reference to visualization tests to fix test errors.
Add an asm loft file for testing.
Use mesh builder to build meshes. Need to reenable back face rendering and get ordering correct on Revit meshes.
Revit triangles wrapping right way around again.