BasicTestbed is only useful for reads

[bigs]

The current BasicTestbed has some odd holes in its functionality. At present, it will never populate specs or nodes, rendering the attempts to read from those member variables before hitting the disk useless. Peering through the commands sources, it's really used as an elaborate container for the directory path. It would be quite useful (and simplify things across the board) if you could mutate the BasicTestbed via some member methods for doing things such as adding new nodes based on specs. If there's any interest in this, I'll do it this week, as it's quite relevant to my current work.