This adds SPI support to the BMI160, as well as a C driver and a C
example. In addition, some changes were made to more properly detect
and handle errors.
Functions supplied by the bosch_bmi160 driver source code is also
exported and made available to callers who want more than what the
basic driver support. Bus access methods (I2C and SPI) are also now
exposed to both C and C++.
Signed-off-by: Jon Trulson <jtrulson@ics.com>
