Avoid error when date in JSON data has no 'date-parts'.
Merge pull request #14 from davidlesieur/no-date-parts

Avoid error when date in JSON data has no 'date-parts'.
Add a file to log release notes
Add citeproc_py.egg-info to .gitignore
BibTeXParser: fix accent and special character handling
Refactor BibTeXParser._expand_macro()

- move common functionality to dispatch()
- get rid of default()
Refactor BibTeXParser._expand_macro() (2)

- replace the token type/value tuple with a namedtuple
Extend the _expand_macros test case
Use 'macron below' instead of 'low line'
Expand macros defined in the BibTeX preamble
Store macros in Macro objects

- unify ACCENT and SPECIAL macros
Pass through math mode substrings as-is
Handle all escaped characters
Handle special characters defined as CM ligatures
Add more standard LaTeX2e macros to the list
Move macros to a separate module
Improve macro class names
Add more LaTeX non-ascii and punctuation macros
Support for \textcircled

Rename Accent to Combining as it is not just used for accents.
Properly handle combining macro arguments > 1 char

The LaTeX output of \’{aa} and \c{aa} depends on the font encoding, so
we don’t bother with trying to match this behavior. Extra characters in
the macro argument are always appended to the output.