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/cmCPluginAPI.h

@@ -168,10 +168,10 @@ typedef struct
   /* new functions added after 2.4 */
   void *(CCONV *CreateNewSourceFile) (void *mf);
   void (CCONV *DefineSourceFileProperty) (void *mf, const char *name,
-                                          const char *briefDocs, 
+                                          const char *briefDocs,
                                           const char *longDocs,
                                           int chained);
-  
+
   /* this is the end of the C function stub API structure */
 } cmCAPI;