Ignore property #81

Currently, it seems that there's no way to completely ignore a property when mapping. It will always fall back to DefaultTypeMap.

public class MyClassMap : EntityMap<MyClass>
{
   public MyClassMap ()
   {
      Map(x => x.Image).Ignore();
      ...
   }
}

If there's a Image column in MyClass table, that column will still be mapped to MyClass.Image.

Any plan to support the Ignore() option properly?