seems like --gpg-flags would be better off not being publically exposed, but if
it's gonna be promoted, it couldn't hurt to toss in a description so the --help
output makes sense. Yeah, it's pretty obvious, esp. running it, but still.
It's there as an argument, might as well document it.
Added info the the args list and the man page. Should
be fix in 2.7.63 or higher (fixed in cvs )