Problem::Evaluate implementation.

1. Add Problem::Evaluate and tests.
2. Remove Solver::Summary::initial/final_*
3. Remove Solver::Options::return_* members.
4. Various cpplint cleanups.

Change-Id: I4266de53489896f72d9c6798c5efde6748d68a47
diff --git a/internal/ceres/dogleg_strategy_test.cc b/internal/ceres/dogleg_strategy_test.cc
index 24c526e..caa397e 100644
--- a/internal/ceres/dogleg_strategy_test.cc
+++ b/internal/ceres/dogleg_strategy_test.cc
@@ -129,9 +129,9 @@
   scoped_ptr<LinearSolver> linear_solver(
       new DenseQRSolver(LinearSolver::Options()));
   options_.linear_solver = linear_solver.get();
-  // The global minimum is at (1, 1, ..., 1), so the distance to it is sqrt(6.0).
-  // By restricting the trust region to a radius of 2.0, we test if the trust
-  // region is actually obeyed.
+  // The global minimum is at (1, 1, ..., 1), so the distance to it is
+  // sqrt(6.0).  By restricting the trust region to a radius of 2.0,
+  // we test if the trust region is actually obeyed.
   options_.dogleg_type = TRADITIONAL_DOGLEG;
   options_.initial_radius = 2.0;
   options_.max_radius = 2.0;