Torchio

* Add ``datasets`` module
* Add support for DICOM files
* Add documentation
* Add ``CropOrPad`` transform

* Add ``Subject`` class
* Add random blur transform
* Add lambda transform
* Add random patches swapping transform
* Add MRI k-space ghosting artefact augmentation

* Add ToCanonical transform
* Add CenterCropOrPad transform

* Add Resample transform

* Add Pad transform
* Add Crop transform

* Add CLI tool to transform an image from file