Re: [ot][spam][crazy][data] transformer model 'attention' improvement

Meanwhile, in the transformers library, I've compartmentalised calls to Amin Rezaei's code into the modeling_utils source file, so I can do most of the work whether or not the pull request is accepted. If it's not replied to in a timely manner, I can copy the MIT-licenseed implementation (which is a direct copy from the paper) into huggingface's repository later.