add output directory option to oggenc

Currently oggenc produces the output ogg file in the same directory where the input file is. I would like to have a option to specify an output directory e.g. "." or in the longer term even with formatstrings to create an output directory with the artist's and album's name in it or with the path or latest directory from the input files.

Examples:

this one would be nice to have soon: oggenc /tmp/artist-album/01-artist-title.flac -O . # outpufile: ./01-artist-title.ogg

these ones would be nice to have in the long term: (%P describes here the last directory from the path of the input file, alternatively %1p for the last directory and %2p for the last but one and the last directory would be a nice feature, too) oggenc /tmp/artist-album/01-artist-title.flac -O "./%p" # outpufile: ./tmp/Artist-Album/01-artist-title.ogg oggenc /tmp/artist-album/01-artist-title.flac -O "./%P" # outpufile: ./Artist-Album/01-artist-title.ogg oggenc /tmp/artist-album/01-artist-title.flac -O "./%a" # outpufile: ./artist/01-artist-title.ogg