do not disable priv sep user if missing

Build environments may not match the runtime environment, so do
not autodetect the priv sep user. Fixes #43.
fix some unescaped dashes in manpages

Fixes #44.
fix missing passwd fields for preload

Some environments (dash for /bin/sh) go crazy without fully filled passwd
fields. Fixes #45.
Merge pull request #46 from kees/master

fix issues 43, 44, 45