Adds in support for getting the system id of the BLE device.
Changes to how systemID is pulled from the bluetooth characteristic. The characteristic is now pulls the first 3 bytes and last 3 bytes. The byte array is reversed (for little endian) and converted to a hex string.
Fixed typo and removed unused import.
Merge pull request #3 from mikejr83/master

Adds in support for getting the system id of the BLE device.