either what's in NVRAM or what the safe defaults would be if we lack NVRAM.
Then we rename cur_XXXX to actv_XXXX (these are the currently active settings)
and the dev_XXX settings to goal_XXXX (these are the settings which we want
cur_XXXX to converge to).
This probably isn't entirely final as yet- but it's a lot closer to now
being what it should be, including allowing camcontrol to actually set
specific settings.