Pursue Emergent and Multi-pathways

[timothyfcook]

Eventually we should move the data structure and program to allow nodes to be represented in multiple pathways.

Also talking about the idea of pathways being an emergent property. In the future, the program should traverse the entire DAG not just the nodes scoped to a specific pathway. This way users could add vague before_this / after_this information and, over time, contribute to the knowledge graph regardless of the pathway/sub-topic they associate the resource with.