cli: Wait for scale events

Signed-off-by: Lewis Marshall <lewis@lmars.net>
cli: scale with no arguments shows current scale

Signed-off-by: Lewis Marshall <lewis@lmars.net>
test: No need to wait for scaling events

Signed-off-by: Lewis Marshall <lewis@lmars.net>
Merge pull request #520 from flynn/scale-wait

Improve CLI scaling experience