LaTeX template: set secnumdepth to 5 if `--number-sections` specified.

This yields behavior equivalent to the other writers, numbering
level 4 and 5 headers too.
ConTeXt writer: Removed `\placecontent`.

This produced a duplicate toc, in conjunction with `\placelist`.
Canonical way to set TOC depth

Use `\placecontent` instead of `\placelist` as `\placecontent` is easier to
configure.
Minor spacing tweak in context template.
Load microtype after fonts.

Microtype needs to know what fonts are in use and it is suggested that it is aded after loading fonts.
Merge pull request #19 from dfc/master

Change latex template to load microtype after loading fonts
Provide \Oldincludegraphics in beamer like in LaTeX

In the old solution there was no way to use a LaTeX image where only the
height was used to scale the image -- the width was always implicitly
set as well leading to wrong aspect ratios.

Provide a command \Oldincludegraphics which does just what
\includegraphics would do in the LaTeX template. That we the same input
markup could be used for beamer and LaTeX templates.
Added default.opml.
Added reveal.js template.

(From a patch by jamiefolson.)
New version of default.revealjs.

Also note rename:  .reveal_js -> .revealjs.
revealjs template - include pdf css stylesheet by default.
Slidy template: use slidy.js rather than .js.gz.
Docbook template:  Use docbook 5.5.  Closes #25.
LaTeX template:  Changes to make mathfont work with xelatex.

We need the mathspec library, not just fontspec, for this.
We also need to set options for setmathfont.
revealjs template: use remotes by default, set defaults from query hash.
Fixed errors introduced in last revealjs template update.
default.latex: Redefine includegraphics to allow custom options.

Thanks to Bernhard Weichel.
Now, literal \includegraphics commands with square-bracketed options
will work properly.  When no options are given, a default option
limits images to the text width.
default.latex:  Use \ScaleIfNeeded w/ nicer def instead of \maxwidth.
default.beamer:  Added comment to graphics section.
Add class attribute to title slide section tag

It would be useful to have a class attribute for the title slide's section tag. For example, this is useful for setting a background image unique to the title slide.