HAL: Add two new SPI devices

SPIDevice_LSM303D and SPIDevice_L3GD20 added to the enum.
The code has also been formated.
HAL_Linux: LSM9DS0 legacy driver moved to AP_InertialSensor/LSM9DS0/

The new LSM9DS0 driver will consist of the AP_InertialSensor_L3GD20 and
the AP_InertialSensor_LSM303D. For that reason the old LSM9DS0
(consisting of gyro and accel+mag implemented on a single class) has
been moved to a folder.

Legacy LSM9DS0 didn't probe to receive "correct" data.
AP_InertialSensor: L3GD20 driver added

L3GD20 gyro userspace sensor added. The driver constructs
over the implementation of the PX4 Dev Team at
https://github.com/diydrones/PX4Firmware.
AP_HAL: Add support for L3GD20
Copter: Add support for L3GD20
HAL_Linux: Add L3GD20 to the AP_InertialSensor header
AP_InertialSensor: INS_generic example, add support L3GD20
HAL_Linux: SPIDriver add support for L3GD20