Improvements to natural language dictionaries.
Rough-in handling of new "marker" element.
Style changes only.
1. Move inside class "Element" to a first-class class. 2. Handle new "flow" element in the spell-checking.
Move "marker" attributes to an orthogonal element. Add flow element.
Improve order of constructor parameters.
Add handling for xpath and marker attributes in the intermediate file.
Add "marker" attribute for data from the document backing the XML.