examples: show-upgradeable: made it compilable again
doc: examples: show-upgradeable: added to CMake build system
doc: examples: show-upgradeable: ported/refactored for libcupt3
lib: internal: regex: return unique_ptr< sregex >, not shared_ptr< sregex >
lib: format2: fatal2 never returns, mark it as such
lib: internal: regex: return simple sregex, not unique_ptr of it
lib: config: recognize and use the option 'dir::ignore-files-silently'