New gui using dialogs. GUI still needs to be integrated with client/serv...

...er style and other new changes.
@isupeene New dialogs for new functionality. Dialogs are opened through the top menu. Also added about dialog and player name changer. 
GUI changes to be done still:
Make work with client/server backend.
Display Player name when saying whose turn it is rather than just player 1/2. Or just change it to be Your turn and other player's turn. Maybe change to show client's player name in bottom left.
Add buttons for different level AI if we add that based on Assignment 4 feedback.

@isupeene what are you working on currently?/what aren't you working on so I can work on that.
This function is slightly convoluted, but whatever.