Merge pull request #1163 from drewhk/wip-2297-lifecycle-patterns-drewhk

Added patterns for initialization for Scala #2297
Add logging intro, see #2737
Merge pull request #1172 from akka/wip-2737-logging-intro-patriknw

Add logging intro, see #2737
clarify `sender` in preRestart, see #2509

also remove one warning about io-old.rst not being included in any
toctree
document availability of `sender` in supervisorStrategy
Merge pull request #1192 from drewhk/wip-old-io-l10n-fix-backport-drewhk

Fixed broken old-io spec (due to l10n of exception msg)
Merge pull request #1190 from akka/wip-2.1-2509-sender-∂π

Wip 2.1 2509 sender ∂π
enable MiMa 0.1.4 and mask private[akka] change in LoggingBus, see #3066
restore BC in RemoteActorRefProvider.deployer, see #3066
closes #3086
Merge pull request #1193 from akka/wip-3066-BC-2.1-∂π

Wip 3066 bc 2.1 ∂π
Merge pull request #1194 from fommil/release-2.1

closes #3086
Defining vocabulary in the introduction pages #2229