v2.1.0: pytorch, efficientnet, RMSprop

Update version to 2.1.0

v1.1.2: STOA ImageNet ResNet50

ResNet50 (Best): 76.56% top1, 93.19% top5
ResNet101 (Best): 77.68% top1, 93.78% top5
ResNet152 (Best): 78.49% top1, 94.21% top5

v1.1.1: Stable ImageNet50

User variance initializer, disable bias for resnet