mp/setup_aws_s3

1. Don't commit .yml files
2. Allow User to upload a stem via AJAX
3. Create S3File model, S3 Account, and store uploaded Wav and Mp3
4. Play the Mp3 version of a stem
5. Catch most errors for the upload process
6. Use STI on S3File to make Mp3File & WavFile
7. Finding Similar Genres doesn't return the Main Genre in the array anymore