1.0.9
    - Further fixing of indexing functions to separate load_index from get_index
      to get clearer separation of setting safe dir and just wanting the indexing
      contents.
    - Fixed download_safe_files so that it updates the cached index to record the
      new local file copies.


1.0.8
    - Reorganised set_safe_dir and load_index to fix bug with new directories and 
      give cleaner code flow and organisation.
    - Added logical operators & and | for combining searches

1.0.7
    - Moved download_safe_files to use the website download URLs not API
    - Added ability to use tokens for restricted datasets (pretty rare, 
      but requires website URLS)
    - Fixed checking for field names to handle what early versions of safedata_validator missed
