Add polished stills for key scheduling, encrypting, and authenticating.

[justintroutman]

These are polished stills for the sample Pockenacci plaintext, using the external style sets (colorway.tex); first up is #3, for key scheduling and encryption; some amendments to that will likely be made, with authentication added next.

[justintroutman]

Add stills for message authentication. Getting close to merge-ready.

[justintroutman]

Resolved via #3!