[ADD] Add MQTTSN client implementation
[ADD] Added macro for MQTTSN debugging
[ADD] Added Example MQTTSN client
[ADD] Added MQTTSN debug macro
[ADD] Added testing documentation
[MOD] Minor change
Merge pull request #63 from lukaszdmitrowski/master

Google Summer of Code 2014 - MQTTSN client implementation for 802.15.4