Use pssh.

Replace bash-isms with pssh to neatly parallelize cluster operations.

Also, decrease questionably high sleep times.
Approve key to local hostname.
pushd instead of cd
approve keys twice
time the pssh calls
Revert "time the pssh calls"

This reverts commit d9333af0a21d1aff3216471823344f326ef84cfb.
test removing ssh pre-approval