text:list-header is not properly handled

examples

• https://github.com/opendocument-app/OpenDocument.test-private/blob/master/odt/Slow%20Cooker%20Sweet%20Balsamic%20Glazed%20Pork%20Tenderloin.odt

references

• http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html#__RefHeading__1415152_253892949