[FEATURE] activity for transmitting console content

This Activity can be used to send the content of the console to all
users of the running session.
A JUnit test is included.

Change-Id: Id9637cde1233e17812ffe9cf15a5fc9548e89da1
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1121
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>
Tested-by: Jenkins CI