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/array_utils.h b/internal/ceres/array_utils.h
index 99cc8d8..742f439 100644
--- a/internal/ceres/array_utils.h
+++ b/internal/ceres/array_utils.h
@@ -28,7 +28,7 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 //
-// Utility routines for validating arrays. 
+// Utility routines for validating arrays.
 //
 // These are useful for detecting two common class of errors.
 //