Implement Multiplayer Support

[huiyun862]

This pull request does the following:

• You can input the number of players for the game; press new game to set players.
• There is no limit to the number of players; the players will appear on the left panel in individual cards.
• Various buttons are repositioned to more appropriate locations.
• Only one panel is used; this panel will change depending on which player.

It's been a week, so there are many changes to the original repo. Maybe leave this as a new branch?

[NicholasACTran]

I like this implementation. Can you include support for the setting score goal and rolling two dice, both that have been included in the current version?

[huiyun862]

Definitely, but this implementation took longer than expected, and it may take until next Saturday before I have time to work on it again. Since I am trying to complete my 4 pull requests for Hacktoberfest, is it okay if I open a separate pull request that implements the requested features?

[NicholasACTran]

@huiyun862 You can, but we cannot merge this in until those changes are made, since it would erase several features that have been worked on and merged in already.