Fix picking coordinates in 2D when map is rotated.
Add tests for picking and handling mouse input when 2D map is rotated.
Fix picking in 2D with rotated map.
Add tests for picking in 2D.
Update CHANGES.md.
Merge branch 'master' into pickCoordinates2D
Merge branch 'pickCoordinates2D' into picking

Conflicts:
	Source/Scene/Scene.js
	Specs/Scene/PickSpec.js
Implement fast SLERP.
Raise the changed event in CzmlDataSource when CZML is loaded.

Also clarify the documentation in DataSource to indicate that the changed event should be raised when the name or clock changes.
Some tweaks for performance testing.
More performance tests.
Remove performance tests. Use fast slerp implementation with typed arrays. Add one more test comparing with old slerp implementation.
Add fastSquad that uses fastSlerp, tests and doc.
Add an option to control whether the first data source added to Viewer automatically sets the clock.

Also improve the logic so that changes to the clock afterward, indicated by the DataSource changedEvent, update the clock as well.  Fixes #1134.
Don't fire changed event in CzmlDataSource unless clock or name have actually changed.
Update CHANGES.md
Replace getElementsByTagName with a case-insensitive regex to search for TileFormat
Merge remote-tracking branch 'origin/master' into fixDataSourceChanged

Conflicts:
	CHANGES.md
Merge branch 'master' into pickCoordinates2D
Merge branch 'pickCoordinates2D' into picking