moved to scala 2.10.3 + scalaz 7.0.6
Added test for merge/mergeN termination in case of one process is drained
corrected async.toSignal
Initial implementation of new interruptibleAsynchronousHandler
simplified interrupted behaviour
modified execution of processes inside a `Junction` to use new asynchronous interruptible execution
Added idempotent combinator
Introduced stateSignal combinator as a helper for state full asynchronous constructs (private streams)
fixed test so it correctly executes now
corrected signal junction strategy to terminate publisher when it terminates the strategy.
Don't interrupt running task in runUntilStepDone
Merge pull request #4 from radekm/wye-drain-fix

Don't interrupt running task in runUntilStepDone
Added comments, changed evaluation of interrupted process to evaluate the cleanup from `next` process after process was interrupted and completed
final rename + removal of old driver
cached the lazy `p2` in  to assure they are evaluated only once.

this affects : append, fby, onFailure & onComplete
Merge branch 'master' of github.com:scalaz/scalaz-stream into wye-drain-fix
added optional `source` parameter to topic.
renamed idempotent to affine
Merge branch 'master' of github.com:scalaz/scalaz-stream into wye-drain-fix
changed order of sleep in cleanup in test, as it caused sporadic failing