PIMSM: cosmetic
PIMSM: examples moved to a new folder
PIMDM: check that interface works in dense mode, before reacting to received datagrams
PIMSM: cosmetics
PIMSM: refactored Join/Prune state machines
PIMSM: killed (*,G) KeepAlive timers

According to RFC 4601, there are no (*,G) KeepAlive timers
PIMSM: added joinDesired variable and its change event