1. qcloud has a great revolution, the protocol has been changed to implement data template, so the old TencentCloud_SDK developed by us will not work fine now(mqtt still works, but data template will not works fine for recently created product/devices).

2. I merge the official qlcoud sdk(include both the iot-hub and iot-explorer sdk) into the componet/conectivity to support new protocol of data template

3. iot-hub sdk, supply the fundamental iot protocol(like mqtt coap, etc.)
iot-explorer sdk, supply the high level service like data template based on mqtt

4. To know how it works, see qcloud_iot_explorer_sdk_data_template、qcloud_iot_hub_sdk_mqtt example(keil project in board\TencentOS_tiny_EVB_MX_Plus\KEIL\qcloud_iot_explorer_sdk_data_template and  board\TencentOS_tiny_EVB_MX_Plus\KEIL\qcloud_iot_hub_sdk_mqtt)