Separate camera graph-building code out into a separate function
Separate lamp graph building code to a separate function
Porting over graph building code for lamps
Stub for defining shader-nodes graph
Some more stubs and ported over code for shading-related nodetrees + datablocks
Rough port of material graph building
Restore missing brace
Stub for particle-systems stuff
Stub for compositing
Copying over logic for building world graph from materials

TODO: perhaps there needs to be a base function for performing the
graph building functionality on these types of ID-blocks?
Porting over code to clear ID-tags on datablocks which we perform recursive building with
Fleshing out includes - adding all common includes which we're likely to need