Low power slowdown reduced for ConYard

Since C&C has no power-down button (and since price of power plant went up), low-power is extra painful in TD vs. RA. Also, since the cost is higher for power plants now, it means you will be in low-power mode longer since you cannot build a power plant as fast.

So, the solution is to make the low power slowdown 1/2 speed instead of 1/3 speed for Conyard. 

This does not apply to the support queue, only the building queue.