Re-design of the Pattern Renderer Controller

While investigating charting possibilities, it has become clear that the rendering controller needs to ditch the visitor pattern and implement the listener pattern from the controller in the Validation component. This is because the charting renderer needs a full working copy of the KnittingEngine in order to make charting decisions, and a lot of duplicate code was being written to work around this issue. However, it has become clear that the current architecture is unworkable.