DOM, take two

Last night at Too Damn Late[TM], I got some really good ideas which amount to a refactoring of the DOM.

• The accessors should be smart get/set types
• VERBATIM chunks should be containers in the manner of TRIGGERS rather than special cases of TEXT chunks
• I was misusing the 0E0 value; it should be replaced with 'undef'
• Now that both the DOM tree and the text stowage structure are arrays instead of hashes, their additive methods can be rewritten with simple push()es instead of index accesses
• ...and the associated node tracking scalars can be gotten rid of
  

And then a lot of little things auxilliary to these points. And rewrites of the POD to match it all. And a likely painful overhaul of the test suite.

Oh well. That's progress. The Grammarian and its Handlers follow this.