Add Bluetooth classic as a sensor network #69, #195, #90

I think the architecture of the ble sensor network, which does not use
threads per socket, can be applied to DTLS.

Known bug:
Occasionally a timeout error occurs when connecting to RFCOMM.
BLE is not supported yet. I need help to do it.


Signed-off-by: tomoaki <tomoaki@tomy-tech.com>

MQTTSNGateway/src/linux/Threading.h

@@ -95,7 +95,7 @@ private:
 class RingBuffer
 {
 public:
-	RingBuffer(const char* keyDirctory = MQTTSNGW_KEY_DIRECTORY);
+    RingBuffer(const char* keyDirctory = MQTTSNGW_KEY_DIRECTORY);
 	~RingBuffer();
 	void put(char* buffer);
 	int get(char* buffer, int bufferLength);