Pan

* HTML writer: Fixed email javascript obfuscation with `mailto:`
URLs (2280). This fixes a potential security issue. Because
single quotes weren't being escaped in the link portion, a
specially crafted email address could allow javascript code injection.

* Markdown/HTML readers: Avoid parsing partial URLs like
`<www.pandoc.org/blahfoo>` as HTML tags (2277).

* RST reader: allow inline formatting in definition list field
names (Lars-Dominik Braun).

* PDF: Make sure `--latex-engine-opt` goes before the filename
on the command line. LaTeX needs the argument to come after
the options (1779).

* CommonMark writer: fixed tags used for super/subscript.

* ConTeXt template: activate hanging indent for definition lists
(Mauro Bieg).

* Make cabal require `hsb2hs` >= 0.3.1 if `embed_data_files` specified.
This is done by adding `hookedPrograms` in `Setup.hs`, which allows us
to include `hsb2hs` in Build-Tools in cabal.

* Improved Windows installer (thanks to nkalvi).

+ When per-machine installation is chosen, the system path
is updated instead of the user's.
+ An appropriate default is used for per-machine installation
directory.
+ Admin privileges are no longer required for a per-user install

* Travis: unpack sdist for build to catch packaging bugs.

* Improved documentation on where user templates go (2272).

* Added pandoc.1 man page to the repository. It is no longer
built as part of the cabal build process. (This proved too
fragile.) pandoc.1 can be regenerated (`make man/pandoc.1`)
when `README` is changed.

* Copying of the man page now respects `--destdir` (2262).

* Improved error messages for filters. User is now informed if
the filter requires an interpreter that isn't found in the path,
or if the filter returns an error status.

* Ensure target directory is created when installing man page.

* Added files needed for building man page to Extra-Source-Files.

* Man page is now built and installed as part of the cabal build
process. Removed Makefile target for man page.

* Man page changes:

+ Removed `--man1`, `--man5` options (breaking change).
+ Removed `Text.Pandoc.ManPages` module (breaking API change).
+ Makefile target for `man/man1/pandoc.1`. This uses pandoc to
create the man page from README using a custom template and filters.
+ Added `man/` directory with template and filters needed to build
man page.
+ We no longer have two man pages: `pandoc.1` and `pandoc_markdown.5`.
Now there is just pandoc.1, which has all the content from README.
This change was needed because of the extensive cross-references
between parts of the README.
+ Removed old `data/pandoc.1.template` and
`data/pandoc_markdown.5.template`.

* OpenDocument writer: Do not add a carriage return after a hard
line break (Michael Chladek).

* ConTeXt writer:

+ use `\goto` for internal links.
+ Added a `%` at end for `\reference` to avoid spurious space.

* Ignore sandbox on 'make quick'