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/dense_sparse_matrix.cc b/internal/ceres/dense_sparse_matrix.cc
index e18a507..978ac6a 100644
--- a/internal/ceres/dense_sparse_matrix.cc
+++ b/internal/ceres/dense_sparse_matrix.cc
@@ -47,7 +47,9 @@
   m_.setZero();
 }
 
-DenseSparseMatrix::DenseSparseMatrix(int num_rows, int num_cols, bool reserve_diagonal)
+DenseSparseMatrix::DenseSparseMatrix(int num_rows,
+                                     int num_cols,
+                                     bool reserve_diagonal)
     : has_diagonal_appended_(false),
       has_diagonal_reserved_(reserve_diagonal) {
   // Allocate enough space for the diagonal.