README updates: clarify research folder and add samples folder (#2693)
README updates: clarify research folder and add samples folder (#2693)


alexgorban/models,jiaphuan/models,derekjchow/models,alexgorban/models,tombstone/models,alexgorban/models,jiaphuan/models,cshallue/models,tombstone/models,alexgorban/models,tombstone/models,derekjchow/models,derekjchow/models,tombstone/models,cshallue/models,tombstone/models,tombstone/models,derekjchow/models,derekjchow/models,alexgorban/models,cshallue/models,cshallue/models,jiaphuan/models,jiaphuan/models,jiaphuan/models,jiaphuan/models,cshallue/models