Initial work to create dokuwiki write (#386)

In this first version, all dokuwiki files are straight copies of the
media wiki counterparts.
Use \setkeys{Gin}{} to set appropriate defaults for \includegraphics, instead of entirely redefining this command.

Note we also consider the height of images; if an image is too high, 0.8\textheight will be used for beamer slides, and \textheight is used for articles (see http://tex.stackexchange.com/q/11954/9128).

If the user has explicitly provided the width/height options in \includegraphics[], our defaults will be overwritten, and this approach is better than the check `\@ifnextchar[` after \includegraphics because the latter approach simply gives up everything once it sees [, whereas \setkeys{Gin} can keep the good defaults unless they are explicitly overwritten in [].

closes #30, closes #28, and closes #26
Merge pull request #58 from yihui/master

Use \setkeys{Gin}{} to set appropriate defaults for \includegraphics
upquote must be used after fontenc

otherwise single quotes in verbatim environments will be in trouble; see an example at http://stackoverflow.com/a/12852815/559676
Merge pull request #60 from yihui/patch-1

upquote must be used after fontenc
Load upquote after fontenc in latex template.
latex template:  conditionalize author and date.

Thanks to ivoanjo for the patch. Closes #61.
latex template:  Added fontfamily variable.

Thanks to tlvince for the patch.  Closes #50.
latex template: Added linestretch variable that loads setspace.
LaTeX/Beamer templates: Remove conditionalization around date.

This restores the old behavior, where no date was printed
if no date was specified.  If the `\date` command is removed
entirely, standard document classes will print today's date.
Closes #1321.

Partially reverts fc5229df167aa61cdbcf14ce24581b36bb0a5b90.
See #61.
LaTeX template:  fix subtitles.

The old code really requires scrartcl from koma-script.
Closes #1327.
Fixed subtitle in latex template.

See jgm/pandoc#1327.
Added default.haddock.
Merge remote-tracking branch 'jgm/master' into dokuwiki
Merge pull request #65 from claremacrae/dokuwiki

Merge in template file for Dokuwiki support
Added `type="text/css"` to link tags in epub3 template.
Added `lot` and `lof` variables to latex template.

lof = list of figures.
lot = list of tables.
Merge branch 'master' of https://github.com/jgm/pandoc-templates