Docx reader: Fix bug in character styles.

Style handling has been cleaned up, but introduced a bug here. There
wasn't previously a test to catch it.
Docx reader: Test for character styles.
Docx reader: Remove unnecessary plural functions

functions like runElemsToInlines and parPartsToInlines are just defined
in terms of concatting and mapping their singular
version (e.g. `runElemToInlines`). Having two functions with almost
identical names makes it easier to introduce errors. It's easy enough to
just concat and map inline, and it makes it clearer what is going on in
the code.
Merge pull request #1540 from jkr/charStyles

Char styles
Release checklist: No longer need to compile pandoc-dingus.

trypandoc is used.
Updated README in templates to indicate templates license.

The templates are duel licensed, BSD3 and GPL2+.
Makefile:  Added 'quick' target.
Markdown writer: don't escape $, ^, ~ when extensions are deactivated.

`tex_math_dollars`, `superscript`, and `subscript` extensions,
respectively.

Closes #1127.
Include row width in table rows.

Added a property to all table rows where the sum of column widths
is specified in pct (fraction of 5000).
Simplify row width calculation.
HTML reader:  Parse appropriately styled span as SmallCaps.
Docx reader: Change behavior of Super/Subscript

In docx, super- and subscript are attributes of Vertalign. It makes more
sense to follow this, and have different possible values of Vertalign in
runStyle. This is mainly a preparatory step for real style parsing,
since it can distinguish between vertical align being explicitly turned
off and it not being set.

In addition, it makes parsing a bit clearer, and makes sure we don't do
docx-impossible things like being simultaneously super and sub.
Parser: Framework for parsing styles.

We want to be able to read user-defined styles. Eventually we'll be able
to figure out styles in terms of inheritance as well. The actual
cascading will happen in the docx reader.
Docx reader: work with new rStyle.

Just discards info at the moment, so at least it works the same.
Docx Style parser: Basic one now just takes a parent style.

This will make it easier to build the style map from the bottom up (to
avoid any infinite references).
Alias string and runStyle to CharStyle type.
Fixed typo in templates README.
Removed check for PATH variable in running filters.

This cause problems on Windows 8, where the variable is called
`Path`.

Instead, simply trap the exception that will be raised by
`findExecutable` if path is not set.

This should fix #1542.
Docx Parse: build a bottom-up style tree.

Two points here: (1) We're going bottom-up, from styles not based on
anything, to avoid circular dependencies or any other sort of
maliciousness/incompetence. And (2) each style points to its
parent. That way, we don't need the whole tree to pass a style over to
Docx.hs
Docx writer:  Fixed regression, bungled list numbering.

In pandoc 1.13, all lists come out as basic ordered lists.
This fixes that bad regression.

Closes #1544.