Add default case in quad_swarm.c quad_swarm_periodic()
Merge branch 'dev' of github.com:QawsQAER/paparazzi into dev
1. write the data parser of quad_swarm module in quad_swarm.h
  follow the way that module formation do in sw/airborn/modules/multi/formation.h
  No error in compiling for now.
2. TODO finalize the quad_swarm state machine
Merge branch 'dev' of github.com:QawsQAER/paparazzi into dev