Add more FMS data to JoystickState

Specifically:
-Add a more generica game-data string so that we don't have to add new
 fields every year.
-Add the current alliance color.

Change-Id: Ic422ccaf1cddd448176dc59618e9f9a3d008ea23
diff --git a/aos/robot_state/joystick_state.fbs b/aos/robot_state/joystick_state.fbs
index f21b211..1deaa06 100644
--- a/aos/robot_state/joystick_state.fbs
+++ b/aos/robot_state/joystick_state.fbs
@@ -12,6 +12,8 @@
   pov:int;
 }
 
+enum Alliance : byte { kRed, kBlue, kInvalid }
+
 // This message is checked by all control loops to make sure that the
 // joystick code hasn't died.  It is published on "/aos"
 table JoystickState {
@@ -36,6 +38,12 @@
   // useful for testing. The only difference in behavior should be motors not
   // actually turning on.
   fake:bool;
+
+  // Color of our current alliance.
+  alliance:Alliance;
+
+  // String corresponding to the game data string
+  game_data:string;
 }
 
 root_type JoystickState;