Start adding support for 2D and columbus view.
Merge branch 'batching' into columbusView

Conflicts:
	Source/Core/GeometryPipeline.js
Merge branch 'batching' into columbusView
Merge branch 'batching' into columbusView
Merge branch 'batching' into columbusView
Force transform to world coordinates if 2D positions are to be computed.
Add allowColumbusView property to Primitive. Clips indexed triangles at the IDL for 2D/Columbus view.
Merge branch 'batching' into columbusView

Conflicts:
	Apps/CesiumViewer/CesiumViewer.js
	Source/Scene/Primitive.js
	Source/Shaders/Appearances/AllMaterialAppearanceVS.glsl
	Source/Shaders/Appearances/EllipsoidSurfaceAppearanceVS.glsl
	Source/Shaders/Appearances/PerInstanceColorAppearanceVS.glsl
Clip un-indexed triangles intersecting the IDL.
Add columbus view support for triangle strips and fans.
Fix geometry clone to set bounding sphere if result parameter is undefined.
Update appearance shaders.
Merge branch 'batching' into columbusView

Conflicts:
	Apps/CesiumViewer/CesiumViewer.js
Merge branch 'batching' into columbusView
Remove PolygonPipeline.wrapLongitude. This step is now performed in the geometry pipeline.
Add columbus view support for lines, line strips and line loops.
Merge branch 'batching' into columbusView

Conflicts:
	Source/Core/Geometry.js
Fix IDL clipping when the points were on the IDL. Revert/Update the the Cesium viewer examples.
Procedurally alter vertex shader for columbus view.
Check scene mode and columbus view support before updating.