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/ \+$//'

Modules/CMakeJavaInformation.cmake

@@ -13,7 +13,7 @@
 #  License text for the above reference.)
 
 # This should be included before the _INIT variables are
-# used to initialize the cache.  Since the rule variables 
+# used to initialize the cache.  Since the rule variables
 # have if blocks on them, users can still define them here.
 # But, it should still be after the platform file so changes can
 # be made to those values.