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/cmSetTestsPropertiesCommand.h

@@ -17,7 +17,7 @@
 class cmSetTestsPropertiesCommand : public cmCommand
 {
 public:
-  virtual cmCommand* Clone() 
+  virtual cmCommand* Clone()
     {
     return new cmSetTestsPropertiesCommand;
     }
@@ -70,7 +70,7 @@ public:
 
   cmTypeMacro(cmSetTestsPropertiesCommand, cmCommand);
 
-  static bool SetOneTest(const char *tname, 
+  static bool SetOneTest(const char *tname,
                          std::vector<std::string> &propertyPairs,
                          cmMakefile *mf,
                          std::string &errors);