Add the LogLevel OFF that can be used to turn off logging. See #2965

Conflicts:
	akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala
	akka-docs/rst/java/logging.rst
	akka-docs/rst/scala/logging.rst

akka-docs/rst/general/configuration.rst

@@ -95,11 +95,11 @@ A custom ``application.conf`` might look like this::
 
     # Log level used by the configured loggers (see "loggers") as soon
     # as they have been started; before that, see "stdout-loglevel"
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = DEBUG
 
     # Log level for the very basic logger activated during AkkaApplication startup
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     stdout-loglevel = DEBUG
 
     actor {

akka-docs/rst/java/logging.rst

@@ -56,7 +56,7 @@ You almost definitely need to have logging set to DEBUG to use any of the option
 .. code-block:: ruby
 
     akka {
-      loglevel = DEBUG
+      loglevel = "DEBUG"
     }
 
 This config option is very good if you want to know what config settings are loaded by Akka:
@@ -153,6 +153,20 @@ If you want to see all messages that are received through remoting at DEBUG log
 
 Also see the logging options for TestKit: :ref:`actor.logging-java`.
 
+Turn Off Logging
+----------------
+
+To turn off logging you can configure the log levels to be ``OFF`` like this.
+
+.. code-block:: ruby
+
+  akka {
+    stdout-loglevel = "OFF"
+    loglevel = "OFF"
+  }
+
+The ``stdout-loglevel`` is only in effect during system startup and shutdown, and setting
+it to ``OFF`` as well, ensures that nothing gets logged during system startup or shutdown.
 
 Loggers
 =======
@@ -167,7 +181,7 @@ Here you can also define the log level.
     # Loggers to register at boot time (akka.event.Logging$DefaultLogger logs
     # to STDOUT)
     loggers = ["akka.event.Logging$DefaultLogger"]
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = "DEBUG"
   }
 

akka-docs/rst/scala/logging.rst

@@ -57,7 +57,7 @@ You almost definitely need to have logging set to DEBUG to use any of the option
 .. code-block:: ruby
 
     akka {
-      loglevel = DEBUG
+      loglevel = "DEBUG"
     }
 
 This config option is very good if you want to know what config settings are loaded by Akka:
@@ -196,6 +196,21 @@ purposes as it contains exactly the default behavior.
   to look up the logger instance to use instead of the class’ name), and you
   might want to do this also in case you implement your own logging adapter.
 
+Turn Off Logging
+----------------
+
+To turn off logging you can configure the log levels to be ``OFF`` like this.
+
+.. code-block:: ruby
+
+  akka {
+    stdout-loglevel = "OFF"
+    loglevel = "OFF"
+  }
+
+The ``stdout-loglevel`` is only in effect during system startup and shutdown, and setting
+it to ``OFF`` as well, ensures that nothing gets logged during system startup or shutdown.
+
 Loggers
 =======
 
@@ -210,7 +225,7 @@ also define the log level.
     # Loggers to register at boot time (akka.event.Logging$DefaultLogger logs
     # to STDOUT)
     loggers = ["akka.event.Logging$DefaultLogger"]
-    # Options: ERROR, WARNING, INFO, DEBUG
+    # Options: OFF, ERROR, WARNING, INFO, DEBUG
     loglevel = "DEBUG"
   }