Added support for same-token concurrency in Task
Dissociate TaskData from FeederData and create TaskData with unique id in Task
They prefer 0L
Changes after code review
Remove feederData/taskData fixtures in TestTask
Merge branch 'master' into clement-sametoken-concurrency

Conflicts:
	spnl-core/src/main/scala/com/wajam/spnl/Task.scala
Merge pull request #56 from wajam/clement-sametoken-concurrency

Added support for same-token concurrency in Task