Syslog is now used for all error messages, return values in the code should be
used by programmers to see the status of the library/board and syslog can be
used to see quickly from a debugging perspective what has gone wrong. A few
cosmetics where improved as well as a mraa_set_log_level() call where the
syslog log mask can be set directly from libmraa.
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
