Features
- Added support for searching relationships by content in `get_objects_by_content.py`. [164](https://github.com/mitre-attack/mitreattack-python/pull/164)
- Updated copyright year.
- Add font size parameter to svg config. [160](https://github.com/mitre-attack/mitreattack-python/issues/160)
Fixes
- Fixed the placement of the grey subtechnique bars in `svg_objects.py`. [166](https://github.com/mitre-attack/mitreattack-python/issues/166)
- Fixed readthedocs build.
- Fixed bug where self.src wasn't iterable in `get_objects_by_content()`.