provide tools for understanding the dependency graph

[drewbanin]

• produce graph image on dbt compile
• commands for graph inspections dbt list --models some_model_name+

[drewbanin]

Closing this in favor of more specific issues:

• dbt info
• dbt ls

Rendering an arbitrary digraph in python is both a library and artistic nightmare. While graph generation on dbt compile still sounds cool, the sinter graph visualizer fills this void. Closing