Rq-scheduler

* Compatible with RQ >= 0.13 and redis-py >= 3.0. Thanks ericatkin and selwin!
* `scheduler.schedule()` now accepts `meta` argument. Thanks as3445!
* `scheduler.get_jobs()` now returns an iterator. Thanks craynic!

* Fixed lock management error. Thanks chaffeqa!

* Fixed conflicting `-q` parameter from rqscheduler script. Thanks sourcepirate!

* Fixed packaging error

* Added support for custom `Job` and `Queue` classes. Thanks skirsdeda!
* You can now pass in a `Queue` object when instantiating the scheduler as such `Scheduler(queue=queue)`. Thanks peergradeio!
* Fixes a crash that happens when the scheduler runs for longer than sleep interval. Thanks chaffeqa!
* Added `job_description`, `job_id`, `job_ttl` and `job_result_ttl ` kwargs to `enqueue_at` and `enqueue_in`. Thanks bw, ryanolf and gusevaleksei!
* You can now run `rqscheduler` with `--quiet` or `-q` flag to silence `INFO` level log messages. Thanks bw!
* Scheduler will now enqueue jobs at exactly the defined interval. Thanks hamx0r!
* You can now run multiple schedulers at the same time. Thanks marcinn!

* Added `scheduler.count()`. Thanks smaccona!
* `scheduler.get_jobs()` now supports pagination. Thanks smaccona!
* Better `ttl` and `result_ttl` defaults for jobs created by `scheduler.cron`. Thanks csaba-stylight and lechup!