kickstart: Set gecos when adding a user
livecd.py: Messages to track hybrid ISO creation
livecd.py: Make isolinux-debug.bin manually selectable
kickstart: Change default kernel arguments to accomodate dracut
livecd.py: Simplify plymouth check
livecd.py: Make x86_64 live images boot

Mer doesn't have /lib64 because it doesn't support mixing 32-bit and
64-bit binaries but the lack of /lib64 is a problem for us because
dracut won't find ld-linux-x86_64.so without it.

With this hack we link /lib64 to /lib until the filesystem package is
up to date.