Made mqtt_sn_receive_packet public
Corrected various spelling mistakes of the word receive
Changed data argument for mqtt_sn_send_packet() to const void* and removed len argument
Changed data argument for mqtt_sn_send_publish() to const void*
Add mqtt_sn_validate_packet()
Whitespace
Refactored read_packet_from_serial() to be more like mqtt_sn_receive_packet()
Added debug message when opening serial port
Added use of select() to make interrupt signals cleaner