* Depend on pandoc 1.12.
* Added yaml dependency.
* `Text.Pandoc.XML`: Removed `stripTags`. (API change.)
* `Text.Pandoc.Shared`: Added `metaToJSON`.
This will be used in writers to create a JSON object for use
in the templates from the pandoc metadata.
* Revised readers and writers to use the new Meta type.
* `Text.Pandoc.Options`: Added `Ext_yaml_title_block`.
* Markdown reader: Added support for YAML metadata block.
Note that it must come at the beginning of the document.
* `Text.Pandoc.Parsing.ParserState`: Replace `stateTitle`,
`stateAuthors`, `stateDate` with `stateMeta`.
* RST reader: Improved metadata.
Treat initial field list as metadata when standalone specified.
Previously ALL fields "title", "author", "date" in field lists
were treated as metadata, even if not at the beginning.
Use `subtitle` metadata field for subtitle.
* `Text.Pandoc.Templates`: Export `renderTemplate'` that takes a string
instead of a compiled template..
* OPML template: Use 'for' loop for authors.
* Org template: '#+TITLE:' is inserted before the title.
Previously the writer did this.
* Moved code for translating listings language names to
highlighting-kate names and back from LaTeX reader to Highlighting.
* Text.Pandoc.Highlighting no longer exposed (API change)
* Text.Pandoc.Highlighting exports toListingsLang, fromListingsLang
Previously header ids were autogenerated by the writers.
Now they are generated (unless supplied explicitly) in the
markdown parser, if the `header_identifiers` extension is
selected.
In addition, the textile reader now supports id attributes on
headers.
Taking into account new context/latex output, and fixing
some bugs in the test suite Tests.Helpers and Tests.Writers.ConTeXt.
(We had the wrong order of expected/actual in the diff output.)
