Uses portable end of line instead of \n in error message
Print error messages on stdandard error instead of standard output
Improved option -x support

Print an error message when the command doesn't exist
Exit with an error code instead of 0
Merge pull request #57 from swaeku/master

Improved error messages
Merge branch 'master' of git://github.com/akrennmair/newsbeuter

* 'master' of git://github.com/akrennmair/newsbeuter:
  Improved option -x support
  Print error messages on stdandard error instead of standard output
  Uses portable end of line instead of \n in error message