persisting ReservationStarted- and EndedEvent

these events only occur once in the new semantics hence they can be stored.
implementing getNonFinalizedReservations query

added a query for getting reservations not in finalized state (e.g. in made, started, ended or cancelled).

For these reservations the current state has to be recovered.
adding iwsn messages

ReservationOpenedEvent, ReservationClosedEvent, ReservationFinalizedEvent
Rewriting lifecycle management in ReservationManager
extending internal messages, updating protobuf dependency

Adding ReservationEvent types (OPENED, CLOSED, FINALIZED)

the actual protoc bin generates java code incompatible with protobuf 2.4.1. Using protobuf 2.6.0 (newest) fixes this issue.
forwarding life cycle events to external plugins
handling finalization/ cancellation in Start- and StopCallable