corrected error message for wheels lookup

VectoCore/VectoCore/Models/Declaration/Axle.cs

@@ -39,7 +39,7 @@ namespace TUGraz.VectoCore.Models.Declaration
 {
 	public class Axle : SimulationComponentData
 	{
-		public object WheelsDimension { get; internal set; }
+		public string WheelsDimension { get; internal set; }
 
 		[Required, SIRange(0, 100)]
 		public KilogramSquareMeter Inertia { get; internal set; }

VectoCore/VectoCore/Models/Declaration/Wheels.cs

@@ -48,7 +48,7 @@ namespace TUGraz.VectoCore.Models.Declaration
 
 		protected override string ErrorMessage
 		{
-			get { return "Auxiliary Lookup Error: No value found for Wheels. Key: '{0}'"; }
+			get { return "Wheels Lookup Error: No value found for Wheels. Key: '{0}'"; }
 		}
 
 		public override Entry Lookup(string key)