Setting tag sfa-2.0-5

Setting tag sfa-2.0-5
client: sfi -a / -p deprecated (use -s instead)
client: sfi cleaned up
client: sfi has backward support for APIv1 aggregates again
server: only APIv2 is supported and should be rather strict
server: settings for turning on/off caching in sm or am
server: plc-dependant code has moved from aggregate to pldriver
server: driver interface extended accordingly