added Higher and Lower priorities
added tests
updated composer
Changed WorkerInterface (worker has now an ID)
added log messages that will help to find bugs and give a look inside the manager
re-worked exceptions to use unused exception class
added new priority names to worker factory
Merge remote-tracking branch 'origin/1.1.x' into 2.0.x
fixed problem with priorities read from comments had invalid values
moved docblock parser to Priority class
added WorkerFactoryInterface
updated doc comment for Worker queues getWorkers method
removed getWorkers() from worker queue interface
changed the way unique id is generated for workers - now factory takes care of what is being created
updated log messages sent from event manager
workers __toString must return a string (cast added)
updated tests that reflect signature changes for Worker
BC-BREAK!  - updated EventManagerAwareInterface (signature changed)
updated manager log message during addWorker
Fixes #1
updated readme and changelog