[modules] baro ets start delay
[modules] airspeed ets start delay
[nps] Started to add fixed wing support in NPS
[dfu] Small fix to finddevs timeout
[system] add apt preference file for lpc21isp package
additionals to use amsys sensors to measure airspeed
[math] fix ecef_of_[ned|enu]_i
[modules] remove unused baro_x_updated vars
[math] buf fix on geodetic function
[rotorcraft] add MODE_STARTUP to make flying without RC possible

Based on Freek van Tienen's commit, thx.
closes #467 for now
[lpc21] print error if trying to use SPI0 with HAL
[rotorcraft] improve in_flight detection heuristic

Simply checks if thrust, speed and acceleration are above a threshold.
Does not rely on RC thrust command anymore, but only on actual thrust command.
Not tested on real vehicle at all so far...

Attempt to improve issue #201 and replaces #468
[boards][krooz_sd] fix PPM Capture/Compare InterruptEnable define
[stm32] include stm32/flash.h instead of f1/4 variants
[ahrs] remove HIGH_ACCEL_FLAG

It is way too dangerous and not needed anymore with the latest imu
sensor. Keeping it for arduimu just in case
[stm32] F4: fix ppm input timer frequency for TIM2

- krooz: don't use TIM2 for PWM
- change to 6 ticks per usec to fit all frequencies
- on the F1 we assume to run at 72MHz for HCLK and both timer clocks
  TIM1 -> APB2 = HCLK = 72MHz
  TIM2 -> 2 * APB1 = 2 * 36MHz = 72MHz
- on the F4 we assume 2 * AHB clock:
  TIM1 -> 2 * APB2 = 168MHz
  TIM2 -> 2 * APB1 = 84MHz

closes #470
[electrical] don't try to use ADC_CHANNEL_CURRENT in SITL
[imu][aspirin_2_spi] clear naming for mag axes assignment
[krooz] add imu driver for KroozSD board from Sergei
[rotorcraft] fix MODE_STARTUP

- init nav, guidance and stabilization from autopilot_init
- after init of the above, set the autopilot_mode so it propagates to the guidance submodes.
- also call autopilot_init after the ahrs_init for ahrs_is_aligned check...