EPUB Reader: Added EPUB reader
Except Compat: Updated to export more module functions
Options: Added option to turn on epub html extensions
HTML Reader: Extended HTML Reader to recognise EPUB specific elements
HTML Reader: Added support for anchors on links and list items
HTML Reader: Added ability to read MathML formatted <math> blocks
EPUB Reader: Integrated into program
EPUB Reader: Added tests
README: Updated with EPUB information
EPUB Reader: Now uses the new MediaBag for images
Docx Parser: Produce endnotes.

The parser had been changing footnotes and endnotes into footnotes. This
isn't a problem, because pandoc collapses them, but the parser should
maintain as much of the docx structure as is collapsed, and let the
toplevel reader worry about how to translate it into Pandoc. (This would
be an issue when, as is planned, the docx parser spins off into its
own module.)

The output is the same, so no test change is required.
Merge branch 'epubend' of https://github.com/mpickering/pandoc into mpickering-epubend

Conflicts:
	pandoc.cabal
Use `mapM_` instead of `() <$ mapM` in one place.
Clean up `mediaTypeOf` a bit.
Use `stripPrefix` where appropriate.
Remove dangling `where` from one function.
Remove redundant isHexDigit function.
Add PatternGuards pragmas.
Slightly fix readability of main program file.
Use texmath 0.7 interface.