DevKit SDK 1.6.2

Two years passed since I got my first IoT DevKit prototype board in hand (5 in total), and now tens of thousands of people are playing with it.

Love and struggle, it's my feeling and also feedback from all of our lovely customers, RESONANCE.
We're keeping improving this lovely board: add new functions, improve the SDK, add new examples, build new development tool - IoT Device Workbench extension for VS Code, and also try our best to help people in thechat room.

Now another spring, another step forward, let's have SDK released for this lovely board and all lovely customers.

• Fix all build warnings pump up from underlying RTOS and libraries.
• Support un-sorted server cert chain during TLS handshake, this is part of TLS 1.3 feature.
• Upgrade Azure IoT C SDK to 1.2.14.
• Remove the path information from the system error which is bothering everyone and may case people feel uncomfortable.
• Support customzied WebServer for system configuration: WiFi setting, IoT Device Connection String setting and X.509 cert setting.
• Support customized time server.

Thanks everyone for using and supporting us! Please try 1.6.2 and any feedback will be appreciated.