fix issue #44

Added menu item to quickly go to "NO Load"
The intent was not a solution for Issue #30 (On/Off) but to have the current set value reset to 0 so as to avoid having to (slowly) bring it down manually. As such, I don't think "Load OFF" would be appropriate. "0 load" though... would. (Also, I have to test latest changes in #52, bringing the set value to 0 might not be so slow anymore)