Add function to compute distance between a point and a boudning sphere.
Remove separate passes. Have primitives add commands to a list and have the renderer sort it all out. Picking is broken though.
Merge branch 'master' into sorting
Use same structure of having commands give a pass when picking.
Add translucent sorting.
Fix tests.
Merge branch 'master' into sorting
Updates from review.
Fix tests.
Merge branch 'master' into sorting

Conflicts:
	Source/Scene/Scene.js
Add option to disable sorting for composite primitives.
Merge branch 'master' into sorting

Conflicts:
	CHANGES.md
Merge branch 'master' into sorting

Conflicts:
	Source/Core/BoundingSphere.js
	Specs/Core/BoundingSphereSpec.js
Merge branch 'commands' into sorting

Conflicts:
	Source/Renderer/Pass.js
	Source/Scene/Scene.js
Merge branch 'master' into sorting

Conflicts:
	CHANGES.md
Implement stable merge sort for testing.
Some tweaks.
Merge branch 'master' into sorting

Conflicts:
	CHANGES.md
Merge branch 'master' into sorting

Conflicts:
	CHANGES.md
Merge branch 'master' into sorting

Conflicts:
	CHANGES.md