Initial rough sketches for the DOM API.
Rough DOM building setup.
Dedicated DOM builder class for CDATA tags.
Rake task for generating code coverage.
Tests for the various XML node types.
Renamed XML::Builder to XML::TreeBuilder.
Tests + docs for the TreeBuilder class.
Tests for TreeBuilder#on_document.
Lex/parser XML declaration attributes.
Dedicated handling of XML declaration nodes.
Tests for XML::TreeBuilder#on_comment.
Tests for XML::TreeBuilder#handler_missing.
Lexer tests for single quoted attributes.
Fixed typ.
Lex/parse doctype names separately.
Tree building of doctypes.
Document should not inherit from Node.

A document is not an XML node on itself. If logic has to be shared between the
Document and the Node class I'll resort to using mixins for this.
Insert newlines after XML dec/doctypes.
Rough setup for a custom #inspect format.

This format is a lot more readable than the default Ruby #inspect format
(mostly due to not including previous/next/parent nodes).
Properly indent doctype/XML decl inspect values.