Version 0.8 is out

Refactoring:

• Refactoring of Pushable for new concurrency model (API-breaking change)
• Duplicate method can copy a processor's state

Bugfixes:

• Group processor cloning that contains sinks
• UniformProcessor's pullable

Additions:

• Added ChangeArity processor
• A few more utility functions
• Added the notifySources option to GroupProcessor
• Added convenience method to GroupProcessor
• Added TurnInto