progress bars for more commands

[jbenet]

would be nice if these had progress bars when there is a tty:

ipfs refs -r
ipfs pin add -r
ipfs pin rm -r
ipfs repo gc

[jbenet]

cc @rht possible to take this on, since you know the progress bar stuff very well now?

[rht]

This depends on how '-r' is done in each of the case. Will update.

[gammazero]

Not sure how we would do this for ipfs refs -r? When starting a refs traversal like this we have no idea how big the graph actually is, nor even how many nodes it contains.