-------------
Features added
~~~~~~~~~~~~~~
* Config versioning support.
The config files can now have a section ``meta`` with the key ``version``.
The version is specified in dotted-notation with a major and minor number
(f.ex.: ``version=2.1``). Configuration instances take an optional
``version`` argument as well. If specified, config_resolver expects the
``meta.version`` to be there. It will raise a
``config_resolver.NoVersionError`` otherwise. Increments in the major number
signify an incompatible change. If the application expectes a different major
number than stored in the config file, it will raise a
``config_resolver.IncompatibleVersion`` exception. Differences in minor
numbers are only logged.
Improvments
~~~~~~~~~~~
* The ``mandatory`` argument **has been dropped**! It is now implicitly assumed
it the ``.get`` method does not specify a default value. Even though
"explicit is better than implicit", this better reflects the behaviour of the
core ``ConfigParser`` and is more intuitive.
* Legacy support of old environment variable names **has been dropped**!
* Python 3 support.
* When searching for a file on the current working directory, look for
``./.group/app/app.ini`` instead of simply ``./app.ini``. This solves a
conflict when two modules use config_resolver in the same application.
* Better logging.