Attempt to allow getting radar values without PN.

src/Steps.cpp

@@ -589,7 +589,11 @@ public:
 	}
 	static int GetRadarValues( T* p, lua_State *L )
 	{
-		PlayerNumber pn = Enum::Check<PlayerNumber>(L, 1);
+        PlayerNumber pn = PLAYER_1;
+        if (!lua_isnil(L, 1)) {
+            pn = Enum::Check<PlayerNumber>(L, 1);
+        }
+        
 		RadarValues &rv = const_cast<RadarValues &>(p->GetRadarValues(pn));
 		rv.PushSelf(L);
 		return 1;