Enable the FourScore adapter for Micro Mages

[troyjfarrell]

I found that adding this line to FCEUGameCore.mm enables up to four players for Micro Mages:

diff --git a/FCEUGameCore.mm b/FCEUGameCore.mm
index 54a8a54..83b8c63 100644
--- a/FCEUGameCore.mm
+++ b/FCEUGameCore.mm
@@ -185,7 +185,8 @@ static __weak FCEUGameCore *_current;
                                 @"90d2e9f0", // K.Y.F.F. (Homebrew) http:https://slydogstudios.org/index.php/k-y-f-f/
                                 @"1394ded0", // Super PakPak (Homebrew) http:https://wiki.nesdev.com/w/index.php/Super_PakPak
                                 @"73298c87", // Super Mario Bros. + Tetris + Nintendo World Cup (Europe)
-                                @"f46ef39a"  // Super Mario Bros. + Tetris + Nintendo World Cup (Europe) (Rev A)
+                                @"f46ef39a", // Super Mario Bros. + Tetris + Nintendo World Cup (Europe) (Rev A)
+                                @"4e6b9078"  // Micro Mages (USA) (Unl) (Homebrew) http:https://morphcat.de/micromages/
                                 ];
 
     // Most 3-4 player Famicom games need to set '4 player mode' in the expansion port

I didn't find any upstream for FCEU-Core that contains FECUGameCore.mm, so I think this is the right place for this.