gpg has an annoying "feature": it avoids to overwrite files. If in interactive mode, "gpg2 -o foo" will ask the user whether to override foo or not, otherwise will just refuse to work. not nice. working around this by making gpg2 write to stdout, and redirecting stdout to that file. Then restore stdout for sanity :) While here, also make `writepass' fail if gpg fails.

'gen' now is happy to override files. since we're using a version control system anyway, there's no point in being picky about changing files. If one overrides a password by mistake, the old one is still available thanks to got.