* Rework optim folder
* Removed TORCH_OPTIMIZER_CLASS macro
* Got rid of CRTP/Impl
* Removed TORCH_AUTOGRAD_KWARG
* Differentiate between Optimizer and LossClosureOptimizer
* Make Optimizers parameters based instead of model based
* Allow construction of optimizer from arbitrary vector
* Added test for zero grad
* Added test for external parameter vectors
* Now comparing against baseline values
* Documentation
* Post rebase fixes
* Different strategy for creating and accessing buffers in optimizers
* Fix member ordering
