[REFACTOR] renamed methods and variables in PN & SN classes

Change-Id: Ib96cfa3681caa2f47f39413279784dfa0caa29e8
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1938
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>