refactor ellipse computation into functions
finished extrusion
tests
circle geometry extrudes correctly
Merge branch 'batching' into extrudeEllipse

Conflicts:
	Source/Core/EllipseGeometry.js
Merge branch 'master' into extrudeEllipse

Conflicts:
	Source/Core/EllipseGeometry.js
use GeometryAttributes object
Merge remote-tracking branch 'agi/master' into extrudeEllipse
Fix issue #356

This removes the logic from the LabelCollection that attempt to prevent the texture atlas used from growing unbounded. This code negatively impacts performance and can create a hiccup affect during animation. The problem it is attempting to address is most likely not to be encountered in the real world and if we ever run into it, we can revisit this issue.
Merge pull request #952 from AnalyticalGraphicsInc/issue356

Fix issue #356
Fix CesiumWidget render loop

`scene.initializeFrame` needs to be called before anything else happens.  By calling `clock.tick` first, listeners to the tick even were seeing the system in a mismatched state (i.e. the camera could think you were in one scene mode while the scene thought you were in another.  This manifested itself in an easy to reproduce crash:

1. Load simple.czml in Viewer
2. Click on a satellite and follow it.
3. Morph to another mode and click to cancel the morph halfway through
4. Crash.

This change fixes that issue.
Use a more compact ID for labels
Actually destroy texture atlas when destroying labelcollection.
Merge pull request #956 from AnalyticalGraphicsInc/fix-viewer-crash

Fix CesiumWidget render loop
Merge pull request #957 from AnalyticalGraphicsInc/labelImprovements

Label improvements
minor cleanup
Merge branch 'master' into extrudeEllipse
sandcastle example
Merge pull request #942 from hpinkos/extrudeEllipse

Extrude ellipse