Habanero

(2015-12-02)
- Fix wheel file to be a universal to install on python2 and python3 (25)
- Added method `csl_styles` to get CSL styles for use in content negotiation (27)
- More documentation for content negotiation (26)
- Made note in docs that `sample` param ignored unless `/works` used (24)
- Made note in docs that funders without IDs don't show up on the `/funders` route (23)

- Now compatible with Python 2x and 3x
- `agency()` method changed to `registration_agency()`
- New method `citation_count()` - get citation counts for DOIs
- New method `crosscite()` - get a citation for DOIs, only supports simple text format
- New method `random_dois()` - get a random set of DOIs
- Now importing `xml.dom` to do small amount of XML parsing
- Changed library structure, now with module system, separated into modules for
the main Crossref search API (i.e., `api.crossref.org`) including higher level methods
(e.g., `registration_agency`), content negotiation, and citation counts.