added dontRecomposite
SuspendEvents also suspends recompositing on CompositeDynamicObjectCollection
Issue: https://github.com/AnalyticalGraphicsInc/cesium/issues/1452
make `shouldRecomposite` 'private' as `_shouldRecomposite`
performance fixes
TimeIntervalCollection, DataSourceCollection, BillboardCollection, ImageryLayerCollection, LabelCollection, PolylineCollection, SensorVolumeCollection
Update CHANGES.md
Remove proxy from most default imagery providers.

ESRI and OpenStreetMap (OSM, Stamen, and MapQuest) all now support CORS headers directly.

Also remove `FeatureDetection.supportsCrossOriginImagery` and related checks which only applied to old WebKit versions (Safari before version 6).
Add polyline loops.
Add Sandcastle example.
Add tests.
Update CHANGES.md.
Tweak CHANGES.md
Add second parameter to Material.fromType to override default uniforms.
Merge pull request #1521 from AnalyticalGraphicsInc/polylineLoop

Polyline Loop
Merge branch 'master' into materialUniforms

Conflicts:
	Apps/Sandcastle/gallery/Polylines.html
Update after merge.
Update CHANGES.md.
Tweak CHANGES.md
Merge pull request #1522 from AnalyticalGraphicsInc/materialUniforms

Material.fromType uniforms
Remove unused modules.