Scale based on perimeter

Scaling is now performed based on perimeter rather than area. This
avoids problems with super skinny triangles giving huge Euclidean
distances. Removed log transform.
Added Bonferroni-corrected significance lines

Since we're running the data through 8 distance metrics, the .05 alpha
level is reduced to .00625, giving 2-tailed z-score confidence level of
z = 2.734369. Lines are now plotted on the graphs for both significance
levels.