jgm/pandoc: pandoc 2.0.5

Fix a bug in 2.0.4, whereby pandoc could not read the theme files generated with --print-highlight-style (#4133). Improve JSON serialization of styles.

Fix CSS issues involving line numbers (#4128). Highlighted code blocks are now enclosed in a div with class sourceCode. Highlighting CSS no longer sets a generic color for pre and code; we only set these for class sourceCode.

--pdf-engine-opt: fix bug where option order was reversed (#4137).

Add PowerPoint (pptx) writer (Jesse Rosenthal). It works following the standard Pandoc conventions for making other sorts of slides. Caveats:

• Syntax highlighting is not yet implemented. (This is difficult because there are no character classes in Powerpoint.)
• Footnotes and Definition lists are not yet implemented. (Notes will usually take the form of a final slide.
• Image placement and auto-resizing has a few glitches.
• Reference powerpoint files don't work dependably from the command line. This will be implemented, but at the moment users are advised to change themes from within Powerpoint.

Create shared Text.Pandoc.Writers.OOXML module (Jesse Rosenthal). This is for functions used by both Powerpoint and Docx writers.

Add default pptx data for Powerpoint writer (Jesse Rosenthal).

Add empty_paragraphs extension.

• Deprecate --strip-empty-paragraphs option. Instead we now use an empty_paragraphs extension that can be enabled on the reader or writer. By default, disabled.
• Add Ext_empty_paragraphs constructor to Extension.
• Revert "Docx reader: don't strip out empty paragraphs." This reverts commit d6c58eb836f033a48955796de4d9ffb3b30e297b.
• Implement empty_paragraphs extension in docx reader and writer, opendocument writer, html reader and writer.
• Add tests for empty_paragraphs extension.

Markdown reader:

• Don't parse native div as table caption (#4119).
• Improved computation of column widths in pipe tables. Pipe tables with lines longer than the text width (as set by --columns) are now scaled to text width, with the relative widths of columns determined by the ratios between the header lines. Previously we computed column widths using the ratio of header line lengths to column width, so that tables with narrow header lines were extremely thin, which was very rarely the desired result.

LaTeX reader: fix \ before newline (#4134). This should be a space, as long as it's not followed by a blank line. This has been fixed at the tokenizer level.

Muse reader (Alexander Krotov):

• Add test for #disable-tables directive in Emacs mode.
• Don't allow emphasis to be preceded by letter.
• Add underline support in Emacs Muse mode..
• Support multiline directives in Amusewiki mode

Man writer: omit internal links (#4136). That is, just print the link text without the URL.

Markdown reader: accept processing instructions as raw HTML (#4125).

Lua filters (Albert Krewinkel):

• Use script to initialize the interpreter. The file init.lua is used to initialize the Lua interpreter which is used in Lua filters. This gives users the option to require libraries which they want to use in all of their filters, and to extend default modules.
• Fix package loading for Lua 5.1. The list of package searchers is named package.loaders in Lua 5.1 and LuaJIT, and package.searchers in Lua 5.2 and later.
• Refactor lua module handling. The integration with Lua's package/module system is improved: A pandoc-specific package searcher is prepended to the searchers in package.searchers. The modules pandoc and pandoc.mediabag can now be loaded via require.
• Bump lower bound of hslua. The release hslua 0.9.3 contains a new function which makes using Haskell functions as package loaders much easier.

reveal.js template: add title-slide identifier to title slide (#4120). This allows it to be styled more easily.

LaTeX template: Added support for pagestyle variable (#4135, Thomas Hodgson)

Add -threaded to ghc-options for executable (#4130, fixes a build error on linux).