ClangTidy cleanups

1. NULL -> nullptr
2. foo.reset(new Bar) -> = foo = std::make_unique<Bar>()
3. Missing std library includes & prefixes

Change-Id: I260b261b484554be681ee5a7398126fdb3b3a789
diff --git a/internal/ceres/cubic_interpolation_test.cc b/internal/ceres/cubic_interpolation_test.cc
index 3907d22..03b1aae 100644
--- a/internal/ceres/cubic_interpolation_test.cc
+++ b/internal/ceres/cubic_interpolation_test.cc
@@ -226,7 +226,7 @@
                                       const double b,
                                       const double c,
                                       const double d) {
-    values_.reset(new double[kDataDimension * kNumSamples]);
+    values_ = std::make_unique<double[]>(kDataDimension * kNumSamples);
 
     for (int x = 0; x < kNumSamples; ++x) {
       for (int dim = 0; dim < kDataDimension; ++dim) {
@@ -335,7 +335,7 @@
 
   template <int kDataDimension>
   void RunPolynomialInterpolationTest(const Eigen::Matrix3d& coeff) {
-    values_.reset(new double[kNumRows * kNumCols * kDataDimension]);
+    values_ = std::make_unique<double[]>(kNumRows * kNumCols * kDataDimension);
     coeff_ = coeff;
     double* v = values_.get();
     for (int r = 0; r < kNumRows; ++r) {