CircuitGraphPlot: fix issue with PCA array having bogus entries at the end.
CircuitGraphPlot: new function loadAll.
Accepts a continuation function as argument.
CircuitGraphPlot: added TODO about potential but harmless error.
CircuitGraphPlot: new function exportCSVAll and associated button.
To export all data--signal flow, eigenvectors, betweenness centrality,
anatomy and PCA--into a CSV file.