fix bad scale when all branch lengths are = 0 and aligned faces exist
Merge branch 'optimal_scale' into stable
added some more tests
fixed bug when rendering rectangular trees with optimal_scale_level=full and 0 branch lengths
Merge branch 'optimal_scale' into stable
removes the creation of a test.svg file every time a tree is visualized.
Merge branch 'stable' of github.com:jhcepas/ete into stable