~~~~~~~~~~~~~~~~~~
* Default location for the configuration file is the
initial working directory.
* Enhanced syntax for method :meth:`RecordList.filtered`.
E.g. instead of ``records.filtered(lambda r: r.type == 'active')``
it's faster to use ``records.filtered(['type = active'])``.
* Support unary operators even for Python 3.
* Basic sequence operations on :class:`Env` instance.