Be silent when skipping unaffected files.

The previously default notice about skipping these files will only appear with
verbosity level 2 from now on.
Restructured man page, rephrased some sections.
Rephrased the file name modification section.

Already specified the not yet implemented -S option.
More options: multi -e and -S.

Documented these features.
Removed the obsolete --version/-V options: they did not work anymore
since I switched from cvs-based releases to continuous github-based
development.