Improved XML entity handling.
Pagemill_SimpleXmlElement::LoadHtml() suppresses errors and asXml() converts special characters to XML entities.
New tests and spec file.
Pagemill_Data unit tests.
Markdown formatting in spec.
Pagemill_Tag->doctype() returns a vanilaa Pagemill_Doctype if no other has been specified or inherited.
Pagemill_Tag tests.
Pagemill_Parser choked on recursive DOCTYPE declarations.
Reinstated HTML entity handling in Pagemill_Parser.
Pagemill_Tag->doctype() can return null.
Fixed doctype entity handling.