navigator mavlink log info messages: add #audio tag
fw autoland: remove confusing slopelength parameter
fw autoland: completely remove the virtual wp between the last wp and the landing wp. autoland starts now from the last normal wp.
fw autoland: fix warning
fw autoland: remove old comments
fw autoland: add very short comment
navigator: remove all but one [navigator] tag from mavlink audio messages
Merge pull request #664 from thomasgubler/beta_audio

navigator mavlink log info messages: add #audio tag
Merge pull request #682 from thomasgubler/beta_fwautoland

Beta: fw autoland remove virtual waypoint
Merge remote-tracking branch 'px4/beta' into fix_mission_dive

Conflicts:
	src/modules/navigator/navigator_main.cpp
l1_pos_control: prevent NaNs for roll setpoint
l1_pos_control: set gndspeed_undershoot to 0 in loiter
l1_pos_control: fix stupid 'if not' mistake
Merge remote-tracking branch 'px4/fix_mission_dive' into beta_mavlink