MaixPy
New features
* Add WiFi API
* display.show's fit arg now default to FIT_CONTAIN
Bug fix
* yolov5 load one label always failed issue
System
* Update APP Store support MaixHub scan download install.
* Update Settings APP:
* support backlight setting
* support auto start APP setting
* optimize Power setting
* optimize WiFi connect
* Classifier APP now display as squre
* Optimize system start speed, now faster
* Add error hint when bootup init display failed