support for：
ONNX (.onnx, .pb, .pbtxt),
Keras (.h5, .keras),
CoreML (.mlmodel),
Caffe2 (predict_net.pb, predict_net.pbtxt),
MXNet (.model, -symbol.json)
TensorFlow Lite (.tflite).
experimental support for ：
Caffe (.caffemodel, .prototxt),
PyTorch (.pth),
Torch (.t7),
CNTK (.model, .cntk),
PaddlePaddle (model),
Darknet (.cfg),
scikit-learn (.pkl),
TensorFlow.js (model.json, .pb)
TensorFlow (.pb, .meta, .pbtxt).
