PIM: moved definition of SourceAndGroup to the base class
PIMSM: added missing destructors
PIMSM: renames
PIMSM: added sendToIP() method + renames
PIMSM: deleted sendPIMJoinTowardSource() method
PISM: eliminated multDataInfo struct (and a memory leak)
PIMSM: split sendPIMJoinPrune() to sendPIMJoin()/sendPIMPrune() (+ eliminated a memory leak)
PIMSM: refactored timers (+ fix some memory leaks)

replaced custom timer classes with cMessages and context objects