[REFACTOR] removed smurf naming from IsInSarosSession method

Renamed to IsInSession. Also deprecated getJID() method.

Change-Id: Ic5e935c84af7246d2b4e978dcbe9e6de1dc50b91
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1613
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>