mraa: updating to the latest version

MRAA is a low level skeleton library being developed by the software and services group at Intel and is incorporated into the IOTDK.

The version on my build of the IOTDK was 0.4.5. I used the following procedure to update to 0.5.0.12. opkg is a package management system with the binary files required for the i586 architecture on the galileo and edison boards.

echo "src mraa-upm http://iotdk.intel.com/repos/1.1/intelgalactic" > /etc/opkg/mraa-upm.conf
opkg update
opkg install libmraa0