Sorry people, when I rearranged the logic in e29a05f for:
$desired_temp1 < $weighted_temp < $desired_temp2
I ORed instead of ANDed, but didn't test it until I just pushed out my
ansible config to that host right now, several months later!
Ordering of ramping cases was a bit over the shop, so cleaned up.
Comment about slope definitions was out of sync. Comment about
$demand range clarified. Some mathematical terms bracketed to be
less ambiguous. Fixes#5.
