Revert changes to viewExtent. Move check for zero vector sooner and adjust if needed.
Update CHANGES.md.
Fix onDataSourceRemoved, and move onDataSourceChanged.
Viewer can now track which data source has the active clock.
Fix developer error when zooming creates an invalid frustum. Also fix crash when attempting to normalize the zero vector during translation in 2D.
Merge branch 'master' into cameraZoom2D

Conflicts:
	CHANGES.md
Merge branch 'master' into viewExtent

Conflicts:
	CHANGES.md
Add a formatError function that tries harder to display useful error information.
xs
Fixes #1124.
Make "scale" private since it's an implementation detail.
Merge pull request #1442 from AnalyticalGraphicsInc/selection-api

Make "scale" private since it's an implementation detail.
Removed DCO for changes that were not merged
Use HTTPS for Bing services and tiles when the document is HTTPS.

A new option "tileProtocol" can be used to force the protocol.
Comment tweaks
Merge remote-tracking branch 'origin/master' into formatError
Merge remote-tracking branch 'origin/master' into bingHttps
Update CHANGES.
Merge pull request #1436 from AnalyticalGraphicsInc/clock-tracking

Clock tracking
Merge remote-tracking branch 'origin/master' into formatError
Merge remote-tracking branch 'origin/master' into bingHttps
Fix non-webGL IE 11 specs.

This addresses all failing non-webGL IE 11 tests except for the DataCloneError failures related to web workers.