HTML reader: Really ignore DOCTYPE and xml declarations.

This actually does what d71b013841f3c9c8c595591e312a31df16a728cb
said it did.

Revised epub tests to remove the repeated DOCTYPE and xml tags.
EPUB test renaming.

Renamed epub test files so they're identified more clearly as
epub:  features.{epub,native} -> epub.features.{epub,native},
and similarly with formatting.{epub,native}.

Added epub test files to cabal file, so they'll be included in
the tarball.
Got rid of Namespaces.
Merge branch 'nonamespace' into streamlineMath

Conflicts:
	src/Text/Pandoc/Readers/Docx/OMath.hs
Finish getting rid of namespaces.