Initial lab outline for Pruning lab
Refactored some code that was getting a bit confusing because of some misnomers.

E.g., Node.parent_node_value() and Node.parent_node_str() really didn't have anything to do with parents necessarily, and their purpose was to get a value from a node if it was a node, otherwise the value itself. Renamed to Node.param_value() and Node.param_str()
Adding submitted report to version control.