Remove references to the context in preparation for move to web worker.
Merge branch 'master' into geometryWebWorker
Add a taskDispatcher that farms out tasks to multiple other workers by inspecting the parameters, requiring in the module, and routing the event.
Move more stuff around for move to web worker.
Add geometry batching pipeline to a web worker.
Merge branch 'master' into geometryWebWorker

Conflicts:
	Source/Core/GeometryPipeline.js
Fix draw call by passing the value of the primitive type to drawElements/drawArrays.
Re-add per instance attributes and also move that to the web worker.
Re-add bounding spheres.
Re-enable editing of per-instance geometry attributes.
Merge branch 'master' into geometryWebWorker
Move ellipsoid and box geometry creation to web worker.
Move circle and ellipse creation to web worker.
Move polygon, polyline, and sphere geometry creation to web worker.
Move cylinder and wall geometry creation to web worker.
Move extent geometry creation to web worker.
Merge branch 'master' into geometryWebWorker

Conflicts:
	Source/Core/WallGeometry.js
Fix after merge.
Fix jsHint errors.
Fix Core tests.