Torch autodiff DFT-D3 version 0.0.2

Changelog

• fix dimensions of reference C6 coefficients
• add helper routine for masking
• ensure autodiff w.r.t. positions works

Full Changelog: v0.0.1...v0.0.2

Initial version of torch autodiff DFT-D3

Implemented features:

• batched processing of geometry inputs
• pairwise rational damping function of the Becke–Johnson scheme
• atom-resolved dispersion energies
• support for autodiff w.r.t. damping parameters and positions