Update LightMQTT.swift
Update LightMQTT.swift

Update code to Swift 3. Avoid unnecessary data copying by using UnsafeMutablePointer instead of UInt8 array. Move from delegate protocol to closures and add closure that returns pointer to message buffer. Add a background DispatchQueue add read from InputStream in this queue, so message parsing does not need to happen in main thread.
PasiSalenius/LightMQTT