LANL Ti model

[reverendbedford]

This PR adds a LANL model for single crystal Ti deformation.

[tianjuchen]

All checks have passed 😄 @reverendbedford

[reverendbedford]

Actually this is pretty good. There are a few specific comments but generally,

1. Change how you're dealing with the sizes of things so that the model would work for any number of slip and twin systems (suggestions in comments).
2. Add documentation
3. Clean up the formatting (indentation mostly)

Once you do that I can see a couple of places we can make this run faster and then we'll be done.