Add resuming functionality to job:result

[nahi]

An user had a problem to download a large result file (over 200MB) and convert it to TSV (this size could be over 2GB) using following command:

$ td job 5632435 -o /Users/anwarelbizanti/Downloads/results.tsv -f tsv

But it failed due because of network problem. Idea here is that job:result resumes downloading if it failed because of network problem.
I guess that you can add some code to td-client-ruby. If downloading failed due to network error, it can send GET request again with Range header.