Add the extra options section, which includes 'Narcissism Mode'

I was inspired by one of the gifts from this year's 12 Days of Holiday Bullshit.

When I received a card with my own name printed on it, I thought it would be cool to give players the option to insert white cards bearing their own names into the game.

One caveat is that the extra cards are added when the game starts, so the set of players that are in the game at the time it starts get white cards. Players who enter later don't get white cards added for them and players who leave don't cause white cards to be removed. I think this is how it should work, though.

I haven't had a chance to test this fully but I thought I'd send the pull request to get your thoughts. At this point, I can verify that the app launches without Javascript errors, that the extra options checkbox group appears when starting a game, and that the initDecks function recognizes when the "Narcissism Mode" option is turned on and off. When "Narcissism Mode" is turned on, I can see the card with my name on it in the log. To be fully confident this change works, I need to try it in an actual game with more people.

Happy holidays~!
EB