* ./src/interface/main.c: tidied the help output code.

  * ./src/interface/main.c: tidied the help output code.
  * ALL: removed underscores from option names and made a few options more
    self-explanatory, for instance --input_channel becomes --audio-channel;
    run vlc -H to see what has changed.
  * ALL: replaced many occurences of "plugin" with the word "module".
  * ./src/interface/main.c: moved all satellite-specific configuration options
    to the satellite plugin.
  * ./po/*: updated translations.