* In PostTrainLinearQuantizer - moved 'clip_acts' and 'clip_n_stds'
  to overrides, removed 'no_clip_layers' parameter from __init__
* The 'no_clip_layers' command line argument REMAINS, handled in 
  PostTrainLinearQuantizer.from_args()
* Removed old code from comments, fixed warnings in 
  test_post_train_quant.py
* Updated tests
* Update post-train quant sample YAML

* Some refactoring to enable multiple clipping methods
* BREAKING: clip_acts as a boolean flag (either in command line
  or in function signature) will fail. Error message with valid
  values from is displayed.
* Implemented clipping activations at mean + N * std
  (N is user configurable)
* Additional tests
* Updated docs

Not backward compatible - re-installation is required

* Fixes for PyTorch==1.0.0
* Refactoring folder structure
* Update installation section in docs

Summary of changes:
(1) Post-train quantization based on pre-collected statistics
(2) Quantized concat, element-wise addition / multiplication and embeddings
(3) Move post-train quantization command line args out of sample code
(4) Configure post-train quantization from YAML for more fine-grained control

(See PR #136 for more detailed changes descriptions)

* Asymmetric post-training quantization (only symmetric supported so until now)
* Quantization aware training for range-based (min-max) symmetric and asymmetric quantization
* Per-channel quantization support in both training and post-training
* Added tests and examples
* Updated documentation