Add args_parser to take input options
Expect metadata to be returned from ffmpeg
Have ffmpeg take an output_extension
Add audio_only option
Remove video channel if audio_only is passed
Remove audio_only

Turns out ffmpeg is smart if you pass a .wav extension
Write end-to-end spec for audio only
Whitespace
Bump version
Use the input file extension by default
Update gemspec with new homepage and ruby version
Update readme
Merge branch 'av-arguments'

* av-arguments:
  Update readme
  Update gemspec with new homepage and ruby version
  Use the input file extension by default
  Bump version
  Whitespace
  Write end-to-end spec for audio only
  Remove audio_only
  Remove video channel if audio_only is passed
  Add audio_only option
  Have ffmpeg take an output_extension
  Expect metadata to be returned from ffmpeg
  Add args_parser to take input options