Updating tickets (#749, #750, #751, #752, #753, #754, #755, #763, #764, #766, #767, #768)

please, someone, add comments on what is to be done. If something, an associated deprecation ticket for 1.2 should be generated.

It's not solidified and is open for discussion.

I think that isRunning, isShutdown etc needs to be removed, since they do not make any sense (racy) and does not work in a distributed setting AND will be replaced by the lifecycle monitoring planned for 2.0

Should these methods:
channel, reply, reply_?, senderFuture, sender etc remain on ActorRef even if they only makes sense inside Actor?

etc etc

Updating tickets (#684, #883, #886, #995, #1017, #968, #969, #973, #1002, #1016, #1021, #1035, #1048, #1119, #1156, #1451, #231, #470, #595, #599, #639, #655, #687, #691, #692, #693, #724, #728, #729, #749, #751, #755, #765, #766, #767, #769, #770, #771, #772, #784, #785, #807)