Holodeck computers will use power_change() now, who will call their emergencyShutdown() proc. This will make the holodeck shut down if the power of the area dies.
Added a check on the emergencyShutdown to see if the holodeck area is already empty.
Removed the unused togglePower() proc of the holodeck computer.
Small change for the power_change() proc of the holodeck.
Merge pull request #868 from Aranclanos/HolodeckItemCheck

Holodeck computer being affected by area power fix.