AP_Notify: avoid suspend_timer_procs() by using atomic updates in ToshibaLED_PX4
AP_InertialSensor: use lockless structures in MPU9250 driver

this avoids suspending timers when transferring data between main
thread and SPI read thread
HAL_Linux: use a semaphore in suspend_timer_procs()

this is the start of multi-core aware code
Copter: show firmware version on param fetch

fixes pull #1320

thanks Arthur!
Rover: show firmware version on param list
Rover: remove unused variable
AC_AttControl: div-by-zero check for bf-to-ef conversion
AC_AttControlHeli: integrate div-by-zero check for bf-to-ef conversion
Copter: remove get_angle_targets_for_reporting fn

this saves a tiny amount of time by removing the memory copy of a
Vector3f
AC_AttControl: remove debug message