Merge pull request #2392 from Benglin/RC0.7.2_Revit2015

Merged changes from "Assoc update cleanup and added testcases" PR
Update README.md
Merge pull request #2382 from DynamoDS/StabilityDev

Improvements to MTBF tracking with a shutdown registry cookie
Fix MAGN-4451 strange behavior with Run Automatic and Revit Document close/reopen.
Merge pull request #2407 from ke-yu/RC0.7.2_Revit2015

Cherry-pick Randy's pull request 2354
fix for watch handlers not showing element buttons

Conflicts:
	src/DynamoCore/UI/Views/PreviewControl.xaml.cs
Change GCRetain() and GCRelease() order