Since commit 77543bde (Convert CMake-language commands to lower case,
2012-08-13) the CMakeVersion.cmake file contains lower-case 'set'
commands. Teach CMakeVersion.bash to replace the lower-case name
instead of the old upper-case 'SET'.
Move the CMake version number components out of "CMakeLists.txt" into
dedicated file "Source/CMakeVersion.cmake". Set the TWEAK level to the
date explicitly. Add a "Source/CMakeVersion.bash" script to update the
date, thus replacing KWSys DateStamp for CMake. Teach the bootstrap
script to extract the version components from their new location.