Adds option to play 9p with 4 spies

[themeeman]

Adds the option to play 9p with 4 spies. This option won't affect the game at all if the player count is anything other than 9.

[vck3000]

Thanks for the PR!

If possible, could you think of how to indicate this changed game mode in the gameRecord please? We should try to keep the database records clean so that researchers who use the dataset won't get results mixed up.

Also sorry about the couple merge conflicts. Been doing some heavy cleanup!

[themeeman]

Yep no problem

[vck3000]

Looks good! Pending discussing with Besjbo.