HTML writer:  fix case when writerNumberOffet is empty or short.

We add 0s to the end of the list if it's shorter than needed.
EPUB writer:  Temporary step towards a better system for numbering.

With this change, `--number-sections` won't work.  This will
be fixed later.
EPUB writer:  more transition.

Changed toChunks to toChapters.
EPUB writer:  Improved behavior with `--number-sections`.

* Headers with "unnumbered" attribute are not numbered.
  (Nor do they cause an increment in running numbering.)
* Section numbers now work properly, even when there is
  material before the first numbered section.
reference.docx:  Added default content type for emf.
ImageSize:  Added Pdf to ImageType.

So far we have no function to determine PDF's size.
Added PDF to content types in reference.docx.
Docx writer:  Handle PDF images.
osx InstallationCheck script: use full path for sysctl.

Thanks to jonahbull for the suggestion.  Closes #580.
Updated copyright year in README
Refactoring in Docx writer.
Added to RELEASE-CHECKLIST - tag templates repo.
Docx writer:  Create content types and document rels from scratch.

This fixes problems that arise when you edit the reference.docx
with Word.  Word tends to remove things from the `[Content_Types].xml`
and `word/_rels/document.xml.rels` files that are needed (e.g.
references to the `footnotes.xml` file and image default mime types).
So we regenerate these completely rather than taking them from
the `reference.docx`.

We also now encode mime types for each individual image rather
than using defaults.  This should allow us to handle a wider
range of image types.

This mostly addresses #414.  The only remaining issue I can see
is the issue of style IDs, which Word inexplicably changes in
some cases when the reference.docx is saved.  E.g.
`FootnoteReference` becomes `FootnoteReference1`.
Fix example header identifier. Very minor.
Changed style names in reference docx.

FootnoteReference -> FootnoteRef.
Hyperlink -> Link.

Why?  Because the old names got changed by Word when the
reference.docx was edited.  I don't understand why, but this
fixes things.

Closes #414.
LaTeX reader: Handle \caption for images in figures.

Closes #766.
Merge pull request #769 from dfc/fix-readme

Fix example header identifier. Very minor.
Docx writer:  Better treatment of display math.

Display math inside a paragraph is now put in a separate
paragraph, so it will render properly (centered and without
extra blank lines around it).

Partially addresses #742.
LaTeX template:  Load microtype after fonts.

Microtype needs to know what fonts are being used.
Thanks to dfc for the patch.
Updated README on docx styles.