report MSVC target architecture (redo)

This is a redo of #166. I can't push to the original PR, probably because I deleted the branch after it was merged.

This commit reports the MSVC architecture, but keeps the exact same detection logic as before and has no error condition. If `cli /?` has an `x64` in it, then assume 64-bit; otherwise, 32-bit. Sorry about the previous error :/