output the final energy (analog to Riemannian-TR)

dune/gfe/riemannianpnsolver.cc

@@ -191,7 +191,7 @@ void RiemannianProximalNewtonSolver<Basis,TargetSpace,Assembler>::solve()
   Dune::Timer energyTimer;
   double oldEnergy = assembler_->computeEnergy(x_);
   if (this->verbosity_ == Solver::FULL)
-    std::cout << "Energy computation took " << energyTimer.elapsed() << " sec." << std::endl;
+    std::cout << "Energy computation took " << energyTimer.elapsed() << " sec." << ",  final energy: " << oldEnergy << std::endl;
 
 
   oldEnergy = grid_->comm().sum(oldEnergy);