Complete refactoring of the project.

- remove drivers
- complete error handling
- optimize redis calls
- atomicity
- more tests
- simplify API
- remove some features
- graceful shutdown
Add missing test on worker.close.
Force creating queue in worker.
Update readme and comments.
Queue now emits a "created" event.
Add events, fix close process.
Remove unused dependencies.
Pipe queue "error" event to worker.
Misspeling in readme.
Externalize pipe-event module.
Update README.md

Fix copy/paste
Code style.
Optimize simple pop.
Check closed state in the loop.
Merge pull request #11 from neoziro/new-api

Rewriting from scratch