Review revealed that we didn't handle the case when the starting point is an empty string. While this is not a valid .odt file, we simply added a special case to deal with it. Also added tests for the new feature.
Fully implemented features: * Paragraphs * Headers * Basic styling * Unordered lists * Ordered lists * External Links * Internal Links * Footnotes, Endnotes * Blockquotes Partly implemented features: * Citations Very basic, but pandoc can't do much more * Tables No headers, no sizing, limited styling