Loss Symmetry

[aztecman]

Yo I heard you liked symmetry, so we put a symmetry in the symmetry so you can have symmetry while you symmetry.

This branch includes an alternative version of the symmetry which can be run in parallel to or as an alternative to the transformation based symmetry introduced in the latest 5.3 symmetry notebook.

To explain the difference: 5.3 notebook uses a direct transformation on the pixels at a certain point in the iteration process (or multiple points)

The (new) symmetry loss compares each half of the image and applies a bit of force each step of the iteration process to encourage the symmetry.

Symmetry loss includes several features such as offset, twist, switch, and a few others

[aztecman]

Closing this PR. HighDruidMotas has put together a similar PR with less merge conflicts [thanks Motas!]. I'll add on the few remaining changes sometime in the next few days.