2018-04-09, Version 1.2.0

Notable changes

• index.d.ts: remove interface Application of module egg; remove exported interfaces from @types/bull

Because of Egg's singleton mechanism, app.bull actually has two types: Bull.Queue or { get: (name: string) => Bull.Queue}. Declaring a union types will bring unnecessary complexity, so it's better to declare it in user's own index.d.ts.