Combined rebuilder/scanner in one commandline and one UI version, let's name it clrmame for now

Core:

misc: scanner, remove matches from AddPath option now removes ALL matches, no matter if they were just real fill-ins for a missing file or already existing in a rompath
misc: hiding sample specific problems while loading datfile in rebuilder and in scanner when no sample paths are set
misc: scanner, skip not accessible unneeded files (loglevel trace can show information about them)
fixed: using relative paths fails after first scan due to wrong current folder
fixed: when an elapsed time takes less than 0 seconds, no value as elapsed time is shown
fixed: hash calculation of empty files
fixed: scanner, some unneeded files won't be removed but aren't reported either when fix is enabled

UI:

added: scanner, context menu option to show clone names (in full merge mode only) which have issues right beside the set name up to 5, if there are more, you can see all in tooltips
misc: merged rebuilder and scanner, switchable via tabs, can run in parallel (unless path sharing issues are detected)