Add workaround to PolylineCollection to cause memory to grow much, much slower and hopefully not crash Chrome.
SuspendEvents also suspends recompositing on CompositeDynamicObjectCollection
Issue: https://github.com/AnalyticalGraphicsInc/cesium/issues/1452
make `shouldRecomposite` 'private' as `_shouldRecomposite`
Updating Contributing.md to remove confusing link to apache CLAs and updating contributors.md to include Aviture Inc
Merge with master
Use defaultValue.EMPTY_OBJECT.
Merge pull request #1481 from AnalyticalGraphicsInc/emptyObject

Use defaultValue.EMPTY_OBJECT.
Merge pull request #1480 from AnalyticalGraphicsInc/chromeCrashWorkaround

Workaround Chrome bug
Fix bug in WallGeometry where it would fail to create the geometry when all points are withing espilon 6 of each other. Decreased to epsilon 14.
Update CHANGES.md.
Merge pull request #1483 from AnalyticalGraphicsInc/wallGeometry

Fix WallGeometry bug
Remove setting camera constrained axis every frame when following an object or after a home flight. It's a global setting and only needs to be set once.
Merge pull request #1484 from AnalyticalGraphicsInc/constrainedAxis

Camera Constrained Axis
Merge pull request #1469 from Aviture/master

SuspendEvents also suspends recompositing on...
Minor formatting clenaup.
Merge master to gltf