Fix an error when using knockout.track without a list of properties.
Merge pull request #1545 from AnalyticalGraphicsInc/knockoutES5Fix

Fix an error when using knockout.track without a list of properties.
Add a loading indicator to the HTML sanitizer.
Merge pull request #1546 from AnalyticalGraphicsInc/info-loading

Add a loading indicator to the HTML sanitizer.
Merge remote-tracking branch 'upstream/master'