tools/pamusb-conf: tighten --add-device logic

Prevent pamusb-conf from creating a new device when that new device
collides with existing node in the pam_usb configuration file.

Various enhancements

Fixed typographical error, changed accross to across in README.

Because it doesn't work with python3.

Double hyphen inside of comment breaks xml.dom.minidom XML parser, which
is considered "not a bug" by mantainer: http://bugs.python.org/issue24197

when creating system pad file change all occurences of / in the device n...

gnome-screensaver-command Gnome 3 update

Merging patches from Debian to upstream

- Seeding the random number generator from PID and current time
provides very little entropy, as these can be guessed quite closely
by an attacker, so use the kernel's random number generator instead.

They are unnecessary and plus lead to build failure on non-Linux architectures.

- Handle LIBDIR as library installation path.
- Set default for PREFIX,LIBDIR if unset.

Add SD Card support