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/cmConfigureFileCommand.h

@@ -19,7 +19,7 @@ class cmConfigureFileCommand : public cmCommand
 public:
   cmTypeMacro(cmConfigureFileCommand, cmCommand);
 
-  virtual cmCommand* Clone() 
+  virtual cmCommand* Clone()
     {
       return new cmConfigureFileCommand;
     }
@@ -48,7 +48,7 @@ public:
     {
     return "Copy a file to another location and modify its contents.";
     }
-  
+
   /**
    * Longer documentation.
    */
@@ -93,7 +93,7 @@ public:
 
 private:
   int ConfigureFile();
-  
+
   cmNewLineStyle NewLineStyle;
 
   std::string InputFile;