Merge pull request #1 from m2mIO/lwtAndQosSupport

Lwt and qos support
Crash Fixed for reconnection on connection loss. Memory leaks removed by usage of ARC. Added Mac library for x86_64
Library version updated for the Example project
Reconnection fixed after connection error (now reconnection is possible from connection error callback without necessity to create session again)
Closing session when disconnect clicked
Update README.md

license
source code added to public repo
更新组织结构，支持Pods形式
Merge branch 'master' of https://github.com/HagerHu/mqttIO-objC