Incorporate changes from PyTorch 1.3.0 and allow non-square fields

This release takes advantage of the new align_corners=False option in PyTorch's grid_sample() and affine_grid() functions, introduced in PyTorch 1.3.0.
It no longer maintains compatibility with versions of PyTorch prior to 1.3.0.

Additionally, displacement fields can now be rectangular (non-square) without causing issues.

Fix issues with training using inverse()

v0.0.4

Prevent producing NaN in inverse backward pass

Change ndim to ndimension() to support wider range of PyTorch versions

v0.0.3

Change ndim to ndimension() to support wider range of PyTorch versions

Rerelease with fix for affine_field

v0.0.2

[Fix] affine_field incorrect dimensions bug

First public release of torchfields

v0.0.1

[Fix] inverse not working on cpu