* Quaternion code is now functioning - Needs RT demo, profile, and debug.
* Added __FPU_PRESENT to compile defines to ensure proper optimization of AHRS code.
* Code to setup/configure ALL imu devices is now in-place.
* Needs intelligent locking of SPI6 across two IMUs (IMU_ONBOARD and IMU_P3.
* Workaround for SPI1_TX/DMA is in-place.  Needs profile, possible rework to DMA channel-sharing.

Signed-off-by: Anthony Clay <anthony.clay@zarthcode.com>