The default behaviour is significantly changed since the previous
version, so upgrading might require changing the configuration file,
especially if not using it in a fairly standard 464XLAT environment
(e.g., as an SIIT-DC Edge Relay). According to the Semantic Versioning
standard, such changes require the major version to be bumped.
Change "2014-2015" with "2014-2016". Also, I had forgotten to update the
licence comment in the clatd script itself in b5725c0, so fix that too.
Thanks to @ingvarha for noticing!
