GitLab

* enable ~ expression in datasets

* fixed root in __init__ to self.root

Make the labels be 1d tensors of type `np.int64`.
Assign label `0`  to data samples of digit 0. The original dataset assigns them label `10`.

* Add documentation for transforms

* document and remove unused imports in mnist.py

* document lsun, mscoco datasets

* rest of the datasets documented

* Clean up the documentation in other functions

* Add links for datasets

* Add more documentation

* pep8 fix