Win64 Portability Czar

[dabrahams]

Someone needs to make sure everything works on Win64. This is a bit tricky as one commonly ends up with a mix of 32- and 64- bit binaries, and the usual assumptions about \Program Files\ don't apply because 32-bit programs are in \Program Files (x86)\. How that mix is divided can vary per-installation, but I'm not sure we can test all of those configurations. It will be up to you to make sure we don't make any obviously incorrect assumptions and to test and maintain at least one easily-installed 64-bit setup.