[Adv] Significant changes to fastai just pushed

[dillon (Dillon (Paperspace))]

@jeremy @miguel_perez For some reason I cannot repro on a new fast.ai instance. What I did:

1. git pull
2. conda env update
3. source activate fastai
4. add import torch above all other lines
   
   
5. Manually created a /cache/tmp directory and changed

os.makedirs('/cache/tmp', exist_ok=True)
!ln -fs /cache/tmp {PATH}

to

os.makedirs('./cache/tmp', exist_ok=True)
!ln -fs /cache/tmp {PATH}

(missing period on my system but maybe not relevant)

6. run through cells.