Audit cat(1)

1) Fix usage ... spacing
2) use *argv instead of argv[0] in the idiomatic for-loop
3) Stop the naïve usage of "/dev/fd/0" and use plain stdin
   instead (This also makes error-messages more consistent).
4) Add newline before return
5) Remove comma in manpage

README

@@ -11,7 +11,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
     -------         --------------------         ---------------
 =*| basename        yes                          none
 =*  cal             yes                          none
-=*  cat             yes                          none
+=*| cat             yes                          none
 =*  chgrp           yes                          none
 =*  chmod           yes                          none
 =*  chown           yes                          none