GCS_MAVLink: add DO_SET_ROI to common.xml
GCS_MAVLink: regenerated messages
GCS_MAVLink: include AP_Math.h

Required because mavlink_conversions's mavlink_dcm_to_euler function
uses atan2
AP_Math: add M_PI_2 definition

Required when building under arduino
Plane: fixed problem with slow ground station connects

don't trigger the "scheduler out of time" code when in the delay
callback

Thanks to Marijm Slootweg for noticing this!
Copter: switch from NAV_ROI to DO_SET_ROI
Copter: bug fix to ROI to pull target from conditional command queue
Plane: enable CTUN log message by default
Plane: expand docs for TRIM_AUTO
Plane: fixed initial reporting of battery remaining

we were not showing battery remaining 100% until we used some battery
AP_Camera: removed 3 camera trigger types that do not work

the trigger by wp distance, trigger with throttle off and trigger a
transistor all don't work, and are not structured correctly, plus are
dangerous.

The existing relay support can (correctly!) handle the resistor case
without hard-wiring a pin. The "turn off throttle to trigger" idea is
badly broken, it would crash a copter if it worked. We can make it
work properly on planes if there is demand. As it was it didn't work
anyway. 

The triggger by wp distance method was broken, and had no way to
initiate a trigger anyway
Plane: use update_aux() for setting up extra channels
Plane: make wp_distance static

removed hack in AP_Camera library
Copter: make wp_distance static

removed hack with AP_Camera library
Rover: added full camera and mount support
Rover: moved camera parameter indexes

this prevents a conflict with some old parameters
Rover: fixed dead-zone on throttle
Rover: fixed HIL build
Rover: update to 2.43beta2
Plane: make TECS the default speed/height controller