It is a bit awkward to have a title for every frame, but not for the one
that holds the table of contents. Allow users to specify a title if they
wish.
As noted [here](https://tex.stackexchange.com/a/49805) ([beamer
commit here](ff70090f36)),
`noframenumbering` is an undocumented, but long existing option
to disable frame numbering for a particular slide. This is useful
to avoid numbering backup slides.
Removed `--latexmathml`, `--gladtex`, `--mimetex`, `--jsmath`, `-m`,
`--asciimathml` options.
Removed `JsMath`, `LaTeXMathML`, and `GladTeX` constructors from
`Text.Pandoc.Options.HTMLMathMethod` [API change].
Removed unneeded data file LaTeXMathML.js and updated tests.
Bumped version to 2.2.
* LaTeX template: Use `pgfpages` package; this is needed for notes on second screen in beamer
* LaTeX template: Add `beameroption` variable in template
The documentation states that the target format name should match the output format, which isn't the case for `docx`/`openxml`.
This PR adds a remark and a frequently requested example (inserting a pagebreak in docx output) to the documentation.
The resulting PDF can be verified using the Apache PDFBox preflight app.
```
$ java -jar preflight-app-2.0.8.jar test.pdf
The file test.pdf is a valid PDF/A-1b file
```
Instructions on how to install the ICC profiles on ConTeXt standalone can be found in the wiki: <http://wiki.contextgarden.net/PDFX#ICC_profiles>.
If the ICC profiles are not available the log will contain messages like these
```
backend > profiles > profile specification 'sRGB.icc' loaded from '/usr/local/texlive/2017/texmf-dist/tex/context/colors/icc/context/colorprofiles.xml'
backend > profiles > error, couldn't locate profile 'srgb.icc'
backend > profiles > no default profile 'srgb.icc' for colorspace 'rgb'
backend > profiles > profile specification 'sRGB IEC61966-2.1' loaded from '/usr/local/texlive/2017/texmf-dist/tex/context/colors/icc/context/colorprofiles.xml'
backend > profiles > error, couldn't locate profile 'srgb.icc'
backend > profiles > invalid output intent 'sRGB IEC61966-2.1'
```
and the resulting PDF will not be valid PDF/A:
```
$ java -jar preflight-app-2.0.8.jar test.pdf
The file test.pdf is not a valid PDF/A-1b file, error(s) :
2.4.3 : Invalid Color space, The operator "g" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, The operator "G" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, /DeviceGray default for operator "TJ" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, /DeviceGray default for operator "TJ" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, The operator "g" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, The operator "G" can't be used without Color Profile on page 1
2.4.3 : Invalid Color space, /DeviceGray default for operator "TJ" can't be used without Color Profile on page 1
```
However, the PDF will still be generated and the "errors" shown in the log do not break anything.
