Add code for emphasized text

Use a heuristic to decide when italic text is meant to be a math
formula or emphasized text. If the text is more than 2 characters long
and contains only letters and spaces, then it is judged to be
emphasized with \emph{}.
Implement numberless sections

If the section title begins with a *, then a \section*{} title will
be emitted instead of \section{}, i.e. that section will not be
numbered.
Rudimentary table support
Merge branch 'master' into gtk3
Avoid autoreconf warning about obsolete INCLUDES
Use gee-0.8 instead of gee-1.0

Confusingly, the gee-1.0 API is for the 0.6 series.
Update VAPI versions

The modified libgdata VAPI isn't necessary anymore.
Fix wrong return in CodeView

xml_code was returning the HTML code.
Add 'save intermediate' action

This saves the intermediate HTML code and XML code to disk.
Add UTF8/LaTeX equivalents
Process tables

Tables are now transformed into a LaTeX \table float containing a
\tabular environment.
Process footnotes

Math in footnotes doesn't work yet.
Add "overwrite all" option

Adds option to the dialog boxes for saving PNGs: if checked, don't
ask any more whether to overwrite
Handle comments

Transform them into \marginpar elements