implemented mission switch
Conflicts:

	src/modules/commander/commander.cpp

 Author:    fludwig <frieludwig@hotmail.com>

 On branch mission_switch
 Changes to be committed:

	modified:   NuttX
	modified:   src/modules/commander/commander.cpp
	modified:   src/modules/dataman/dataman.c
	modified:   src/modules/dataman/dataman.h
	modified:   src/modules/mavlink/mavlink_mission.cpp
	modified:   src/modules/navigator/mission.cpp
	modified:   src/modules/uORB/topics/mission.h
	modified:   uavcan
fixes and more for mission_switch functionality
Conflicts:

	src/modules/bottle_drop/bottle_drop.cpp
	src/modules/commander/commander.cpp
	src/modules/navigator/mission.cpp
fixes and more for mission_switch functionality
Conflicts:

	src/modules/navigator/mission.cpp
added mission_switch updates from master
fixes for mission switch
fixed init
fixed dataman init
added clear
removed comment
added switch once only
Merge branch 'mission_switch' of https://github.com/friekopter/Firmware into mission_switch

Conflicts:
	src/modules/commander/commander.cpp