refactor(redis): use set instead of hash for unique mode
feature(redis): transactionnal unique push and pop
Merge pull request #12 from neoziro/improve-unique-mode

feature(redis): use of transactionnal operations and set instead of hash
Complete refactoring of the project.
Add missing test on worker.close.
Create queue every times in worker.
Update readme and comments.
Queue now emit a "created" event.
Add events, fix close process.