Add base model and training scripts

@all I've added the PyTorch version of InceptionTime model in model.py and the basic training script in train.py for the unified model, you could see README.md to find the usage. The scripts could be successfully run on both CPU and GPU (tested with CASGPU1 and CASGPU2). Since I'm not quite familiar with PyTorch. Please feel free to tell me if there's anything that could be improved.