Revise C++ coding style using clang-format

Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.

* 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/cmExportSetMap.h

@@ -20,13 +20,14 @@ class cmExportSet;
 class cmExportSetMap : public std::map<std::string, cmExportSet*>
 {
   typedef std::map<std::string, cmExportSet*> derived;
+
 public:
   /** \brief Overloaded operator[].
    *
    * The operator is overloaded because cmExportSet has no default constructor:
    * we do not want unnamed export sets.
    */
-  cmExportSet* operator[](const std::string &name);
+  cmExportSet* operator[](const std::string& name);
 
   void clear();