* added leaky_relu relu6 softplus elu celu logsigmoid
* minor fixes for docstring and benchmark imports
* fixed elu implementation and added tests
* added tests for optional param, changed leaky_relu param to fit pytorch documentation
* added mse_loss, nll_loss and kl_div_loss
* fixed axis not defined error in nll_loss
* fixed axis not defined in kl_div_loss
* added tests for mse, nll and kl_div
* modified docstrings and added reduce helper func
* updated docstring in kl_div_loss and moved helper func
* added new kl divergence implementation
* added reduction to test
* updated docstring of kl_div_loss with correct spelling
* added losses to nn.rst in docs
* MLE and L1 loss functions
* logsoftmax change and tests
* subtract max logit for numerical stability
* l1 name change
* cross entropy reduction + unit tests
* docstrings
* l1 test name change
* old loss impl + default none
* style
* MLE and L1 loss functions
* logsoftmax change and tests
* subtract max logit for numerical stability
* l1 name change
* cross entropy reduction + unit tests
* docstrings
* l1 test name change
* old loss impl + default none
