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/iterative_schur_complement_solver.h

@@ -32,8 +32,9 @@
 #define CERES_INTERNAL_ITERATIVE_SCHUR_COMPLEMENT_SOLVER_H_
 
 #include <memory>
-#include "ceres/linear_solver.h"
+
 #include "ceres/internal/eigen.h"
+#include "ceres/linear_solver.h"
 #include "ceres/types.h"
 
 namespace ceres {
@@ -70,17 +71,17 @@ class Preconditioner;
 class IterativeSchurComplementSolver : public BlockSparseMatrixSolver {
  public:
   explicit IterativeSchurComplementSolver(const LinearSolver::Options& options);
-  IterativeSchurComplementSolver(const IterativeSchurComplementSolver&) = delete;
+  IterativeSchurComplementSolver(const IterativeSchurComplementSolver&) =
+      delete;
   void operator=(const IterativeSchurComplementSolver&) = delete;
 
   virtual ~IterativeSchurComplementSolver();
 
  private:
-  LinearSolver::Summary SolveImpl(
-      BlockSparseMatrix* A,
-      const double* b,
-      const LinearSolver::PerSolveOptions& options,
-      double* x) final;
+  LinearSolver::Summary SolveImpl(BlockSparseMatrix* A,
+                                  const double* b,
+                                  const LinearSolver::PerSolveOptions& options,
+                                  double* x) final;
 
   void CreatePreconditioner(BlockSparseMatrix* A);