Remove trailing whitespace from most CMake and C/C++ code

Our Git commit hooks disallow modification or addition of lines with
trailing whitespace.  Wipe out all remnants of trailing whitespace
everywhere except third-party code.

Run the following shell code:

git ls-files -z -- \
 bootstrap doxygen.config '*.readme' \
 '*.c' '*.cmake' '*.cpp' '*.cxx' \
 '*.el' '*.f' '*.f90' '*.h' '*.in' '*.in.l' '*.java' \
 '*.mm' '*.pike' '*.py' '*.txt' '*.vim' |
egrep -z -v '^(Utilities/cm|Source/(kwsys|CursesDialog/form)/)' |
egrep -z -v '^(Modules/CPack\..*\.in)' |
xargs -0 sed -i 's/ \+$//'

Source/cmLocalVisualStudio6Generator.h

@@ -37,7 +37,7 @@ public:
   virtual void AddCMakeListsRules();
 
   /**
-   * Generate the makefile for this directory. 
+   * Generate the makefile for this directory.
    */
   virtual void Generate();
 
@@ -57,9 +57,9 @@ private:
   std::string DSPFooterTemplate;
 
   void CreateSingleDSP(const char *lname, cmTarget &tgt);
-  void WriteDSPFile(std::ostream& fout, const char *libName, 
+  void WriteDSPFile(std::ostream& fout, const char *libName,
                     cmTarget &tgt);
-  void WriteDSPBeginGroup(std::ostream& fout, 
+  void WriteDSPBeginGroup(std::ostream& fout,
                           const char* group,
                           const char* filter);
   void WriteDSPEndGroup(std::ostream& fout);
@@ -82,8 +82,8 @@ private:
   friend class EventWriter;
   cmsys::auto_ptr<cmCustomCommand>
   MaybeCreateOutputDir(cmTarget& target, const char* config);
-  std::string CreateTargetRules(cmTarget &target, 
-                                const char* configName, 
+  std::string CreateTargetRules(cmTarget &target,
+                                const char* configName,
                                 const char *libName);
   void ComputeLinkOptions(cmTarget& target, const char* configName,
                           const std::string extraOptions,