[rotorcraft] add MODE_STARTUP to make flying without RC possible

- MODE_STARTUP defaults to AP_MODE_KILL (as before), but can be set to AP_MODE_NAV
- 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...
- Added check if autopilot_motors_on do determine if you want to switch to AP_MODE_FAILSAFE
[ardrone2] Parrot GPS show sattelite information.

closes #474
[imu][aspirin_2_spi] clear naming for mag axes assignment
fix google maps version download parsing

also set the default example version to 129
[imu] remove old aspirin2 driver
[imu] aspirin_v2.2: unselect baro at startup

- prevent floating CS line on the MS5611 baro connected via SPI
  so it also works if the baro is actually not read
- this requires to have the appropriate SPI_SLAVE defined in the board file
  which is the case for the lisa autopilots
[fix][fixedwing] init state interface _before_ sensors and ins

This had the very very nasty effect that the local coordinate system was not initialized
if NavSetGroundReferenceHere() was not called from the fliht plan,
(e.g. because not waitinf for GeoInit to finish).