New notification feature!

[Barry Brown]

I added a new feature to the app. In the Settings menu, you can enable a notification to send you a word of the day. I may need to update the wording on the Settings screen to be more clear. The notification feature defaults to off, but from the Settings menu you can turn on the feature.

The notification can be every hour, every 12 hours, or once a day.

Any feedback on this feature would be appreciated!