Test that an Echo-Nest-Remix-compatible version of ffmpeg is installed.

Run the tests like this:
    python test_ffmpeg.py
    
If you want to test that your version of ffmpeg can handle a particular file, 
(like if you're planning on analyzing OggVorbis files and want to make sure
your ffmpeg can decode them), run like this:
    python test_ffmpeg.py my_crazy_audio_file.mp47

If any of these tests fail, chances are you are using a version of ffmpeg
that doesn't have all the codecs it needs installed. To remedy this, either 
find and install the missing codecs, or use the version of en-ffmpeg provided
by The Echo Nest. To use the provided en-ffmpeg, copy the binary appropriate 
to your OS from external/en-ffmpeg/ to the location where your system keeps
binaries (on mac this is /usr/local/bin/).

The audio file provided for testing, input_file.mp3, is "Guppies" by 
Raleigh Moncrief, licensed under a Creative Commons Attribution-NonCommercial License.
http://freemusicarchive.org/music/Raleigh_Moncrief/Vitamins_EP/Raleigh_Moncrief_-_Vitamins_EP_-_02_Guppies