Revise C++ coding style using clang-format-6.0

Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`.  Use `clang-format` version 6.0.

* If you reached this commit for a line in `git blame`, re-run the blame
  operation starting at the parent of this commit to see older history
  for the content.

* See the parent commit for instructions to rebase a change across this
  style transition commit.

Source/cmGlobalVisualStudio14Generator.h

@@ -27,6 +27,7 @@ public:
   void WriteSLNHeader(std::ostream& fout) override;
 
   const char* GetToolsVersion() override { return "14.0"; }
+
 protected:
   bool InitializeWindows(cmMakefile* mf) override;
   bool InitializeWindowsStore(cmMakefile* mf) override;