(svn r1741) - Fix: added IsVehicleIndex() so it's possible to protect GetVehicle() from reading an invalid vehicle index

- Fix: added check for v->type in some commands, which expects v to be a specific type

Checks like this is needed to protect network servers from people, who hack their clients to either cheat or crash the server

NOTE: if I made a mistake here it can make a function unreachable when it should be used. Here is one place to look if something weird happens

vehicle.h

@@ -376,6 +376,14 @@ static inline Vehicle *GetVehicle(uint index)
 	return &_vehicles[index];
 }
 
+static inline bool IsVehicleIndex(uint index)
+{
+	if (index < _vehicles_size)
+		return true;
+	else
+		return false;
+}
+
 #define FOR_ALL_VEHICLES(v) for(v = _vehicles; v != &_vehicles[_vehicles_size]; v++)
 #define FOR_ALL_VEHICLES_FROM(v, from) for(v = GetVehicle(from); v != &_vehicles[_vehicles_size]; v++)