Gumstix u-boot 1.2

I took the plunge and, at the risk of bricking my Verdex, updated u-boot. I can only begin to describe the improvements! The process was not nearly as perilous as I anticipated (though I did hold my breath when I rebooted the first time). Noteworthy improvements are the ability to load the kernel directly into the U-Boot environment, and the inclusion of ymodem file transfers over the serial line. The former reduces my boot time to a breathtaking 23 seconds, while the latter reduces rootfs flash time via serial connection by more than half!