#375 flac: metaflac -- Add short optios for command line use

[Jari Aalto]

Cf. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=616468

Please add short options for typical command line use, like

-l, --list
-r, --remove
-n, --no-filename
-s NAME, --show-tag=name
-i FILE, --import-tags-from=file
-e FILE, --export-tags-to=file
-E FILE, --export-cuesheet-to=file