fw att: robustify main loop against non finite numbers and limit error output rate
fw att: pitch ctrl: robustify against non finite numbers
fw att: roll ctrl: robustify against non finite numbers
fw att: yaw ctrl: robustify against non finite numbers
ardrone interface: reduce stack size of start handler
ardrone interface: reduce stack size

Conflicts:
	src/drivers/ardrone_interface/ardrone_interface.c
Merge pull request #985 from PX4/ardronestacksize

Ardrone interface: reduce stacksize
drivers: Fix compile warnings and non-standard performance counter names
Merge branch 'master' of github.com:PX4/Firmware
mavlink: Compile warning fixes
apps: Compile warning fixes
Merge pull request #988 from PX4/warning_fixes_v2

Warning fixes v2
Merge remote-tracking branch 'upstream/master' into fwattrobustify

Conflicts:
	src/modules/fw_att_control/fw_att_control_main.cpp
fw att: add performance counter
Merge pull request #975 from PX4/fwattrobustify

Make the fw att controller more robust against infinite input
Don't limit speed for 'follow' mission items
navigator: calculate progress and trigger waypoint for 'follow' items more carefully
navigator: avoid equal prev and next follow offsets
navigator: takeoff fix, always reach takeoff altitude, even if first waypoint is lower
rc.mc_defaults: set default acceptance radius (NAV_ACCEPT_RAD) to 2m