Brunnhilde 1.7.2

• Changes to HTML report: now named report.html; CSS updated to Bootstrap 4; significant stylistic changes.
• All CSS and JS requirements for the HTML report are now downloaded locally rather than being linked from CDNs (unfortunately, at this time this means you need an internet connection at the time you run Brunnhilde).
• SQLite database is now removed by default at end of processing. -k and --keepsqlite arguments were introduced to give users the option to retain the database.