Replace some DOC_TBA comments with real doc
Replace more DOC_TBA comments
Improve CompositePrimitive doc
Merge branch 'master' into doc-tba
Rename CompositePrimitive to PrimitiveCollection
Added options to PrimitiveCollection constructor
Replace more DOC_TBA comments
Move various files to their new homes.
Move a bunch of terrain-related types to Core.
Sort requires.
Remove Scene dependency in TilingScheme.js.
Factor Renderer/Scene stuff out of TerrainProvider.
Update CHANGES.md.
Fix test failures.
Fix require order.
Merge pull request #1713 from AnalyticalGraphicsInc/moveTerrainToCore

Move terrain to core
Merge branch 'master' into doc-tba

Conflicts:
	CHANGES.md
Merge pull request #1711 from AnalyticalGraphicsInc/doc-tba

Replace DOC_TBA comments
Merge branch 'master' into gltf-next