Merge pull request #2 from mbatchkarov/old_code

More code
Merge pull request #3 from mbatchkarov/master

Various fixes
Merge branch 'master' of https://github.com/mbatchkarov/DiscoUtils
Updated io_utils.write_vectors_to_disk so that vectors_path can be a file name or a file-like object. Renamed several variables to improve legibility.