fix formatting for (non-generated) internal source files

- Change formatting standard to Cpp11. Main difference is not having
  the space between two closing >> for nested templates. We don't
  choose c++14, because older versions of clang-format (version 9
  and earlier) don't know this value yet, and it doesn't make a
  difference in the formatting.
- Apply clang-format to all (non generated) internal source files.
- Manually fix some code sections (clang-format on/off) and c-strings
- Exclude some embedded external files with very different formatting
  (gtest/gmock)
- Add script to format all source files

Change-Id: Ic6cea41575ad6e37c9e136dbce176b0d505dc44d

internal/ceres/block_sparse_matrix_test.cc

@@ -32,6 +32,7 @@
 
 #include <memory>
 #include <string>
+
 #include "ceres/casts.h"
 #include "ceres/internal/eigen.h"
 #include "ceres/linear_least_squares_problems.h"
@@ -43,7 +44,7 @@ namespace ceres {
 namespace internal {
 
 class BlockSparseMatrixTest : public ::testing::Test {
- protected :
+ protected:
   void SetUp() final {
     std::unique_ptr<LinearLeastSquaresProblem> problem(
         CreateLinearLeastSquaresProblemFromId(2));
@@ -159,13 +160,13 @@ TEST_F(BlockSparseMatrixTest, AppendAndDeleteBlockDiagonalMatrix) {
 
     A_->RightMultiply(x.data(), y_a.data());
     B_->RightMultiply(x.data(), y_b.data());
-    EXPECT_LT((y_a.head(B_->num_rows()) - y_b.head(B_->num_rows())).norm(), 1e-12);
+    EXPECT_LT((y_a.head(B_->num_rows()) - y_b.head(B_->num_rows())).norm(),
+              1e-12);
     Vector expected_tail = Vector::Zero(A_->num_cols());
     expected_tail(i) = diagonal(i);
     EXPECT_LT((y_a.tail(A_->num_cols()) - expected_tail).norm(), 1e-12);
   }
 
-
   A_->DeleteRowBlocks(column_blocks.size());
   EXPECT_EQ(A_->num_rows(), B_->num_rows());
   EXPECT_EQ(A_->num_cols(), B_->num_cols());
@@ -213,6 +214,5 @@ TEST(BlockSparseMatrix, CreateDiagonalMatrix) {
   }
 }
 
-
 }  // namespace internal
 }  // namespace ceres