Pywarm

New:

* Add efficientnet example

* Add namespace in engine

* Add summary_str in util

* Fix compatibility with pre-v1.2 PyTorch involving Tensor.ndim

* Various small bugfixes

New:

* Added `warm.up` as an alias of `warm.engine.prepare_model_`.

New:

- Added layer_norm layer

- Added embedding layer

- New transformer example

New:

- [Transformer layer](https://blue-season.github.io/pywarm/reference/warm/functional/transformer).

- [Dropout layer](https://blue-season.github.io/pywarm/reference/warm/functional/dropout).

- New [MobileNet](https://github.com/blue-season/pywarm/blob/master/examples/mobilenet.py) examples.

Fix links and logos on the readme page.

First release.