* Release notes in readme
* Update example in readme
* Note deprecation of DjrillMessage class
* Longer long_description for PyPI
* Update authors
* Bump version number (setup.py and __init__.py)
* Don't crash if no tags
* Allow `None` to omit options entirely from Mandrill send call
* Default `preserve_recipients` to None (= use setting from Mandrill account)
* ImproperlyConfigured --> ValueError for bad tags