Version bump to 1.13.1.
Updated README date
Makefile:  Add README as dependency of man pages.
Put version in lower-left corner of man pages.
PDF:  Catch errors in conversion of images and display message.

See #1582.
Textile reader: Improved table support.

We can now handle all different alignment types, for simple
tables only (no captions, no relative widths, cell contents just
plain inlines).  Other tables are still handled using raw HTML.

Addresses #1585 as far as it can be addresssed, I believe.
Updated changelog.
DokuWiki writer:  Handle table cell alignments.

Closes #1566.
DokuWiki writer:  Make tables prettier by aligning columns.

Also cleaned up crufty code and added tests.
Makefile: simplified 'make dist'.

Note that this may not work with older cabal versions.
Shared: Moved import of toChunks outside of conditional.

Closes #1590.
Use protocol-relative URL for mathjax.

See jgm/pandoc-templates#67.
EPUB, EPUB3 templates:  Handle structured metadata on titlepage.

Previously we just expected 'title', 'subtitle', 'author', 'date'.
Now we still support those, but also support the format recommended
for epub metadata in the pandoc README:

    ---
    title:
    - type: main
      text: My Book
    - type: subtitle
      text: An investigation of metadata
    creator:
    - role: author
      text: John Smith
    - role: editor
      text: Sarah Jones
    identifier:
    - scheme: DOI
      text: doi:10.234234.234/33
    publisher:  My Press
    rights:  (c) 2007 John Smith, CC BY-NC
    ...
EPUB writer: Don't use opf:title-type for epub2.

It is not supported and epubcheck complains.
README: escape (c) in epub metadata example
Markdown reader:  better handling of paragraph in div.

Previously text that ended a div would be parsed as Plain
unless there was a blank line before the closing div tag.

Test case:

    <div class="first">
    This is a paragraph.

    This is another paragraph.
    </div>

Closes #1591.
LaTeX writer: Put `~` before header in item text.

Because of the built-in line skip, LaTeX can't handle a section header
as the first element in a list item. (To be precise, it can't handle it
if the list immediately follows a section header, but the instance is
rare enough that we can afford to be a bit more general). This puts a
non-breaking space before the header to solve this problem. We won't see
this space, since the header skips a line before printing anyway.

The output is ugly in LaTeX and this structure seems like it should
probably be avoided. But it is valid HTML and native pandoc, so we
should have some sort of typesettable representation in LaTeX.
LaTeX writer: Add tests for header-in-item.
Use real copyright symbol in README epub metadata example.
EPUB writer:  Extract title even from structured title.

Added docTitle'.