Remove update check from about box.

The about box should not conduct its own update check. Doing so creates
the possibility of two simultaneous updates occurring, and the update
download file locking.

This commit also removes two behaviors, ESC to close, clicking on
version number to install update,  which were not thread-safe.
Merge branch 'RC0.7.2_master' into RC0.7.2_Revit2015
Merged changes from "Assoc update cleanup and added testcases" PR
Merge pull request #2391 from Benglin/RC0.7.2_master

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.
Fix MAGN-4451 strange behavior with Run Automatic and Revit Document close/reopen.
Merge pull request #2408 from ke-yu/RC0.7.2_master

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

Conflicts:
	src/DynamoCore/UI/Views/PreviewControl.xaml.cs
	src/DynamoRevit/ViewModel/RevitVisualizationManager.cs
Change GCRetain() and GCRelease() order
Change GCRetain() and GCRelease() order
Merge pull request #2423 from Benglin/RC0.7.2_master

Change GCRetain() and GCRelease() order
Merge pull request #2424 from Benglin/RC0.7.2_Revit2015

Change GCRetain() and GCRelease() order
Do not use CurveLoop in RevitGeometryFromMirrorData method
Fix to handle longest lacing on empty arrays

It used to crash, it now doesn't execute the function

http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4566
Fix to handle longest lacing on empty arrays

It used to crash, it now doesn't execute the function

http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4566
Merge pull request #2438 from junmendoza/RC0.7.2_Revit2015

Fix to handle longest lacing on empty arrays