------------------
* Moved utility functions into ``coaster.utils``
* Bugfix: make ``get_email_domain`` somewhat more reliable
* Switched to using ``coaster.db`` in tests
* New: ``MarkdownColumn`` composite column for Markdown content
* Changed: ``JsonDict`` column will use PostgreSQL's native JSON type if
the server is PostgreSQL >= 9.2
* ``TimestampMixin`` now uses ``datetime.utcnow`` instead of ``func.now``
because the ``now()`` function in PostgreSQL returns local time with
timezone, not UTC time, and discards the timezone component if the column
doesn't store them. This made timestamps local, not in UTC unless the server
was also in UTC
* Database tests are now run against both SQLite3 and PostgreSQL
* Bugfix: ``PermissionMixin`` was mutating inherited permissions
* Bugfix: ``render_with`` no longer attempts to render pre-rendered responses
* ``utils.make_name`` now takes caller-specified counter numbers
* ``sqlalchemy.BaseNameMixin`` and ``BaseScopedNameMixin.make_name`` now take a
reserved names list
* New: ``utils.nullint``, ``nullstr`` and ``nullunicode`` for returning
``int(v)``, ``str(v)`` and ``unicode(v)`` if ``v`` isn't false