Corrected Cooling fan pin assignments

I added logic that will assign the pins for the cooling fans based on two settings.  NUM_FANS  and REPURPOSE_FAN_TO_COOL_EXTRUSIONS.

I have tested this a lot over the last week and simulated every possible senerio.  It works.  If you merge this then I will start directing people to download and use your branch rather than mine.  You have done so much more that I can hardly keep track.  Thank You.