Fix 'Ext_lists_without_preceding_blankline' bug.

  * Fixes #1636.
  * Adds a test.
Getting the page width from the reference file

Uses it to scale images that are too large.
When there is no reference files, default to a US letter portrait size
to scale the images
Org reader: parse LaTeX-style MathML entities

Org supports special symbols which can be included using LaTeX syntax,
but are actually MathML entities.  Examples for this are
`\nbsp` (non-breaking space), `\Aacute` (the letter A with accent acute)
or `\copy` (the copyright sign ©).

This fixes #1657.
Pretty:  Make CR + BLANKLINE = BLANKLINE.

This fixes an extra blank line we were getting at the end
of markdown fragments (as well as rst, org, etc.)

Closes #1705.
Version bump to 1.13.2.

This is needed because of the addition of KaTeX to
HTMLMathMethod.
Merge pull request #1668 from gbataille/widthFromRef2

Getting the page width from the reference file
Merge pull request #1706 from tarleb/org-symbol-entities

Org reader: parse LaTeX-style MathML entities
DOCX writer: Look in user data dir for archive reference.docx.
HTML writer:  Make header attributes work outside top level.

Previously they only appeared on top level header elements.
Now they work e.g. in blockquotes.

Closes #1711.
Docx reader: fix for Issue #1692 (i18n styles)

This patch builds paragraph styles tree, then checks if paragraph has
style.styleId or style/name.val matching predetermined patterns.
Works with "Heading#" (name.val="heading #") for headings and
"Quote"|"BlockQuote"|"BlockQuotation" (name.val="Quote"|"Block Text")
for block quotes.
Docx reader: add tests for i18n headers.

This tests blockquotes and headers in Russian. Previous tests make sure
that this doesn't produce a regression in en-us Header and Blockquotes.
Docx test: Remove Danish header test.

Redundant, now that we're testing for a more generalized sort of
internationalized blocks.
Clarified need for `-s` to get character encoding info.

Closes #1724, #1725.
Strip querystring in ODT write

* Resolve #1682
* Strip querystring from filename before rendering ODT files, ODT cannot
handle querystrings in files.
Merge pull request #1727 from toddsifleet/tws-fix-issue-1682

Strip querystring in ODT write
TWiki Reader: add new new twiki reader
TWiki Reader: add basic syntax test
TWiki Reader: update documentation
ODT writer:  Correctly handle images without extensions.

Closes #1729.
Merge pull request #1726 from AlexanderS/twiki-parser

TWiki Reader: add new new twiki reader