Use Reader.

To avoid to pass opts explicitly around (as we
do not use it very much at the moment anyway)
Docx Reader: Parse omml equations.
Docx Reader: Add new file, TexChar.

This will allow us to deal with unicode characters from word equations. This
part of the process will need to continue to be improved.
Docx Reader: Write LaTeX based on equations in word.

This is a first stab at writing out equations in LaTeX based on
omml equations in Word. There are some glitches: unicode chars not known to
LaTeX are silently skipped, and functions (such as `\oiiint`) not in the
standard LaTeX packages are inserted, which can lead to pdf compilation
errors (depending, of course, on your preamble).

Adding, for example, `\usepackage[charter]{mathdesign}` to the preamble will
allow you to use most of the more esoteric functions.
HLint suggestions.
Move more things to Reader.
Little restructuralization.
Merge pull request #1399 from xkollar/reader

Modad.Reader + HLint for MediaWiki writer
MediaWiki writer: Minor renaming of 'st' prefixed names.
Merge pull request #1397 from jkr/equations

Docx Reader: Parse Docx OMML math/equations
HTML reader:  adjust `blockTags` and `eitherBlockOrInline`.

- Added `audio` and `source` in `eitherBlockOrInline`.
- Moved `video`, `svg`, `progress`, `script`, `noscript`, `svg` from
  `blockTags` to `eitherBlockOrInline`.
- `map` and `object` were mistakenly in both lists; they have been removed
  from `blockTags`.
normalize:  consolidate adjacent RawBlocks when possible.
`Parsing`: Added `stateInHtmlBlock` to `ParserState`.

This is used to keep track of the ending tag we're waiting
for when we're parsing inside HTML block tags.
EPUB writer:  better handle HTML media tags.
Revamped raw HTML block parsing in markdown.

- We no longer include trailing spaces and newlines in the
  raw blocks.
- We look for closing tags for elements (but without backtracking).
- Each block-level tag is its own RawBlock; we no longer try to
  consolidate them (though `--normalize` will do so).

Closes #1330.
Merge branch 'dokuwiki' of https://github.com/claremacrae/pandoc into claremacrae-dokuwiki
Minor line wrapping.
Document DokuWiki writer in README.
Updated dokuwiki tests for latest changes to testsuite.native.
Reorganized some markdown tests.