Reflection API missing in Portable Class Library Profile259

I had the following code working fine in a PCL with TargetFrameworkVersion of 4.0 and TargetFrameworkProfile of Profile104.

 public class AppCapabilitiesRepository : IAppCapabilityRepository
    {
        private readonly Type _typeOfAppCapability = typeof (IAppCapability);

        public IList<IAppCapability> GetCapabilities()
        {
            var capabilities = Assembly.GetExecutingAssembly().GetTypes().Where(IsAppCapability).ToArray();
            var viewModels = capabilities.Select(capability => ((IAppCapability)Activator.CreateInstance(capability)))
                .Where(c => c.IsActive)
                .OrderBy(c => c.Popularity).ToList();
            return viewModels;
        }

        private bool IsAppCapability(Type type)
        {
            return _typeOfAppCapability.IsAssignableFrom(type) && !type.IsAbstract && !type.IsInterface;
        }
    }

After upgrading the project to TargetFrameworkVersion of 4.5 and TargetFrameworkProfile of Profile259, these reflection APIs no longer can be found:

Assembly.GetExecutingAssembly, Type.IsAbstract and Type.IsInterface.

This solution is also using MvvmCross 3.5.1 if this matters.

What do I do now?