My initial thoughts, with the release of the new emojione v3 library and polymer v2 I think its time to bump to the next major iteration.
I think the approach should be
create a new branch for v1.x (legacy)
create a dev branch for development of the latest features and merge later
Also deploy the latest version to npm at v1.0 and here at github. (bower is deprecated) and the upgraded (polymer 2.0 strict) version to v2.0 at npm and github