:new: Rewrite message-registry in ES6
:new: Rewrite message-registry in ES6

e-jigsaw/Linter,levity/linter,JohnMurga/linter,AsaAyers/linter,AtomLinter/Linter,shawninder/linter,blakeembrey/linter,steelbrain/linter,Arcanemagus/linter,DanPurdy/linter,atom-community/linter