NB: Support for Meteor <= 1.2.1 (End of Life)

[gadicc]

Just added this to the README:

At some point later this year (2016), support for Meteor versions below 1.3 will be dropped. You will continue to be able to use your last installed version of msgfmt - indefinitely - but later updates will rely - in a non-backwards-compatible manner - on featuers provided by Meteor 1.3. This co-incides with MDG's roadmap to deprecate Atmosphere and move all core Meteor packages to npm.

New versions will still be on Atmosphere for some time to come, since we are heavily coupled to the Meteor build system for a lot of our "magic". But we'd like to start using ES6+ features and gradually prepare the code for a possible generic npm release in the long term.