Add SDK to Linux C++ project

• 1. Create a C++ project.
• 2. Copy libCommSDK.so/libJsonSDK.so/libLabelMakerSDK.so/libDiscovery.so to your project.
• 3. Import .so files in your program.
• 4. To connect to a printer using the Bluetooth interface, you need to install libbluetooth-dev.

Note: this SDK is developed in:

• x64 ubuntu 16.04 LTS
• x64 CentOS 7
• ARM64 Kylin v10
• ARM64 UOS