v0.3.0

• Add a class to empty del tags so they can be styled by CSS.
• a few minor code reorganizations. moved testing only code to testing files.
• Probably breaks python2 compatibility.
• pin dependency six to single version.
• unpin testing libraries. Old versions do not run with python3. Testing libraries may be pinned again in a future release.
• Incompatible change: remove sort_del_before_ins. Use sort_nodes instead. The default behavior of sort_nodes now uses the same node comparison function.

v0.2.2: Merge pull request #3 from PolicyStat/issue_3

Only call action_insert_node if the node type is an element or text