[FIX] some actions did not release their listeners

Corrected the behavior be implementing the Disposable interface.

Change-Id: Ibf1334e8d54437cb979cd1aaea0698d0f4ca2903
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1226
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>