fix weird bug where elements in ax.collections weren't Affine2D objects but

just matrices, resulting in an AttributeError on t.get_transforms()


Was trying to get the scatter tooltips to work, was getting an "AttributeError: numpy.array does not have attribute get_transforms", hunted down the bug and for some reason my plotter wasn't returning Affine2D objects but instead just matrices. I couldn't figure out why, it didn't have anything to do with the data size. But this seems to work!