refs #23: Added a test showing that list items with no ilvls were throwing errors.
refs #23: early continue if parent does not have an ilvl
Merge branch 'master' into issue_23
Merge pull request #23 from OpenScienceFramework/issue_23

Deleted text in a list breaks setting of list attributes
Merge branch 'master' into issue_25

Conflicts:
	pydocx/tests/test_xml.py