improved toSource
more debug added to mergeNspec
Initial implementation of new asynchronous primitives
Simplify and unify termination behaviour of pipe, tee, wye
Fixed tests for AsyncSignal implemented via WriterTopic
Tested async.writerTopic
Fixed async.Queue
fixed mergeN
More tests for resource safety and exception passing
Merge branch 'topic/process/append3-merge-async' into simplify-unify-termination
Fix killBy
Merge pull request #195 from radekm/simplify-unify-termination

Simplify and unify termination behaviour of pipe, tee, wye