CAMP HANSON, Afghanistan — I’m still at Camp Hanson in a tent without air-conditioning, but before I get any farther into this trip, I thought I’d point out some old-fashioned Marine ingenuity.   While I was at Camp Dwyer, I shared temporary quarters with an embarker from Okinawa.  He shared his interesting way of getting ice-cold water.   While Marines obviously don’t have refrigerators in their tents, the lucky ones do sleep in Alaska Environmental Control Units, or ECUs. As you can see from this photo to the right, they include a long tube that starts on one wall, then makes…