Feature request: resume download after a network error occured

[brainwo]

When a download is failed, re-downloading should continue the download where it left out last time. Also it will be good if there's a retry dialog when download is failing:

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:19 --:--:--     
curl: (6) Could not resolve host: raw.githubusercontent.com
Download failed. Retry [Y/n]:

[yuler]

I think we do this simply by passing curl's -retry