Check robustness of PCA representation

[agitter]

Based on a discussion with @brycejoh16 we realized we should confirm that our PCA representation of a collection of graphs is robust to the order in which the graphs and the edges are presented. We can try randomly permuting the rows and columns of the graph X edge matrix before running PCA and confirm the outputs still pass our test cases.

[ntalluri]

I checked the robustness of PCA. Shuffling the columns (the algorithms) and the rows (the edges) do not change the output of PCA.

[ntalluri]

#185

added pca robustness test to test_ml

[agitter]

Closed by #185