Crossword Client functionality

[johnrearden]

This Epic covers the crossword game frontend and backend, and consists of the following User Stories.

Keyboard Navigation [(https://github.com//issues/2)]
3 Column large screen layout [https://github.com//issues/3]
Add finished button [https://github.com//issues/5]
PB comparison [https://github.com//issues/6]
Maintain seen_crossword list [https://github.com//issues/7]
After completing crossword, give option of starting new one or returning home [https://github.com//issues/16]
Should still see clues on completion [https://github.com//issues/17]