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/cmDocumentationFormatterHTML.h

@@ -32,7 +32,7 @@ public:
                     const cmDocumentationSection& section,
                     const char* name);
   virtual void PrintPreformatted(std::ostream& os, const char* text);
-  virtual void PrintParagraph(std::ostream& os, const char* text); 
+  virtual void PrintParagraph(std::ostream& os, const char* text);
   virtual void PrintIndex(std::ostream& ,
                           std::vector<const cmDocumentationSection *>&);
 private: