Brunnhilde

* A new simpler syntax for calling Brunnhilde: `brunnhilde.py source destination`. The old API (`brunnhilde.py source destination basename`) is officially deprecated but will continue to be supported for API stability.
* New stylings for the HTML report, which no longer require Bootstrap or any external JavaScript or CSS dependencies. This removes the need for an internet connection or for caching asset files locally.
* A new properly-formatted "Virus report" section of the HTML report with its own link in the navigational bar.
* Improved "Duplicates", "Warnings", and "Errors" sections of the HTML report.
* Improving terminal logging, using Python's built-in `logging` module.
* Better handling of output directories. If the output directory already exists, Brunnhilde will now quit with a warning unless the`-o/--overwrite` option is provided.
* Support for running `bulk_extractor` on Windows.

**New features**

* The new `--stdin` and `--csv` options enable Brunnhilde to use a Siegfried CSV file as input from either piped stdin or a file, respectively, if the source being analyzed is a directory (issue 1).
* The new `--hfs_partition` and `--hfs_fsroot` options enable users to specify a partition number or POSIX path to `unhfs` to specify which files should be extracted from HFS disk images (issue 45, with thanks to Brian Dietz, NCSU Libraries).
* The new `--regex` option enables users to pass a regular expressions file to `bulk_extractor` to have bulk_extractor search for custom patterns (with thanks to Joe Carrano, MIT Libraries, https://github.com/tw4l/brunnhilde/pull/49).

**Bugfixes**

* Close connections before deleting the sqlite database (https://github.com/tw4l/brunnhilde/pull/48).
* Empty CSV files are no longer written to the `csv_reports` directory.

* Adds `-v` or `--verbosesf` argument which enables verbose Siegfried logging to the terminal during scanning. This addresses https://github.com/timothyryanwalsh/brunnhilde/issues/40 and should make it easier for users to tell the current status of the Siegfried scan for larger sources.

* Addresses [Issue 38](https://github.com/timothyryanwalsh/brunnhilde/issues/38) by:
* Replacing the `wget` Python module with `requests` (removing the cryptic "-1/unknown" terminal output and improving handling of downloads)
* Adding `--save_assets` and `--load_assets` arguments that allow users to cache and retrieve the HTML report's Bootstrap CSS and JavaScript dependencies at a local filepath of their choosing, removing the need for an internet connection to use Brunnhilde. Previously, Brunnhilde HTML reports linked out to CDNs to render correctly; this was seen to be a preservation risk. The default behavior remains for Brunnhilde to download its Bootstrap dependencies from the Brunnhilde Github repository on each run.
* Renames the `assets` directory to hidden directory `.assets`.
* Fixes buggy formatting in display of Social Security Numbers found by bulk_extractor in the Brunnhilde HTML report.
* Renames the "PII" section of the Brunnhilde HTML report to "SSNs", more accurately reflecting the content being displayed, which is currently only Social Security Numbers. Other features found by bulk_extractor can be found in the `bulk_extractor` output directory.

* 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.

Bugfix release.

* Adds error handling for UnicodeDecodeErrors when writing Siegfried CSV files into the SQLite database.
* Adds error handling for OSErrors when determining file size for files whose filepath is invalid (behavior noticed with trailing spaces in file names and similar naming issues).

* Adds "-l"/"--largefiles" option to support ClamAV scanning of large source directories and files