Merge branch 'replaceGetSetScene' into singleSceneEntry
private context
Use RGB textures for imagery without alpha.

Currently only Bing imagery claims to not have alpha.
Update CHANGES.md.
Merge remote-tracking branch 'origin/master' into noAlpha
Merge branch 'master' into singleSceneEntry

Conflicts:
	Source/Scene/SceneTransitioner.js
	Source/Widgets/HomeButton/HomeButtonViewModel.js
remove context from camera, billboard and scene transforms
createTextureAtlas, sandcastle
Merge branch 'master' into singleSceneEntry
update CHANGES.md
extent -> rectangle
Merge branch 'master' into renameExtent

Conflicts:
	Source/Workers/createVerticesFromHeightmap.js
update CHANGES.md
clear -> removeAll
Merge remote-tracking branch 'origin/master' into noAlpha

Conflicts:
	CHANGES.md
Add specs for hasAlphaChannel property.
Merge pull request #1612 from AnalyticalGraphicsInc/renameExtent

Rename Extent to Rectangle
Merge remote-tracking branch 'origin/master' into noAlpha

Conflicts:
	Specs/Scene/SingleTileImageryProviderSpec.js
Merge branch 'master' into singleSceneEntry

Conflicts:
	CHANGES.md
cleanup