make them follow the elevons

spoiler 1 and 2 are connected to 2 auxiliary channels, functions are
set to 16 on left wing and 17 om right wing respectively. Worked in
FBW + mode (auto etc.). No manual mode supported yet (need more
channels in my case).

fix hud battery text overlaying
tweak hud resize
tweak main switcher
fix quickview text scaleing
fix dist to mav.
added french translation thanks oliver
change tooltip time
add 3dr iv
add distance to home
dataflashlog update

#define modifications for sync symbol detection and center pwm value correction

Switchover : wait for end of PPM frame before switching

Fixed logic problem in the decoder (PPM channel increment)

Added LOG_ITERM default to enabled

Increase other constraints from 3200 to 32000.  These constraints are there to ensure int32_t do not cause an overflow when added to an int16_t.

Changes on behalf of Leonard Hall

Includes replacing flight_mode_strings with print_flight_mode function.
SendDebug macro replaced with direct Serial.print_P calls.

Channel count auto detection post processing code
Added a #define : valid frames threshold before detection validation

Don't think it really needs it, but I feel better with the cast.

removed unused waypoint_radius var
removed slow_wp
updated speed management system to maintain a constant acceleration or deceleration of 1m/s
changed version to 2.8.1a

Particularly important is the roll-pitch I term move from the stabilize to rate controllers.