Integrating gordon with librosa analysis

To use this package, do the following :

1. install the gordon branch from the bmcfee fork: https://github.com/bmcfee/gordon
2. Edit the gordon.ini.default, and either copy it to /etc, or set up an environment variable: export GORDON_INI=/path/to/your/gordon.ini
3. Run the scripts in code/ in alphabetical order:
   • ./S0_init_gordon.py
   • ./S1_generate_index.py REGEXP tracks.json file1 [file2 ...]
   • ./S2_intake_from_index.py "Collection name" tracks.json
   • ./S3_analyze_librosa_lowlevel.py /path/to/low_level/analysis/output
   • ./S3_title_cleanup.py
   • ./S4_analyze_librosa_midlevel.py /path/to/mid_level/analysis/output
   • To update analyses later, run ./S4_update_librosa_lowlevel.py /path/to/analysis/output feature1 [feature2 [ ... ] ]