Sorry for yet another PR here. This one includes @michagogo's suggestions and doc changes. It replaces #6343 and #6342.
Teach gitian to output a -win-unsigned.tar.gz similar to OSX. The signer will attempt to combine any "-unsigned.exe" with a matching "*-unsigned.exe.pem" from the detatched signature repo.
Also note that the new target signature dir for windows has changed from "${VERSION}-win" to "${VERSION}-win-unsigned".
Tested with a phony tag and signature.
Safe for backport, should be good to go for rc3.