Variable Sample Sizes on CIFAR10 + Swish6 Activation Function

This release has:

• You can now define the validation sample size when loading CIFAR-10 and CIFAR-100: #73 . By tweaking this number, you may find bigger test accuracies when training your models.
• There is a new activation function TNNetSwish6. This activation function is a fantastic replacement for ReLU6 as it gives higher accuracy while maintaining numerical stability.