Patches to add minimum and maximum frequencies to powerd(8)

[Boris Kochergin]

Hi, list. A friend asked me if it was possible to tell powerd(8) not to 
throttle lower than a certain frequency, so I hacked something up, then 
thought I'd try my hand at a more proper implementation of minimum and 
maximum frequency specifications, as I recall similar requests on other 
lists.

For interested parties, the patches can be found at 
http://acm.poly.edu/~spawk/powerd/ and are against RELENG_7_0 sources, 
but the changes should be the same for -CURRENT. Comments are welcome.

-Boris