Add scripts to create, sign and verify hashes
Remove unused scripts (moved to utilities repo); add .gitignore
Make udev rules opt-in

Some users reported graphics freezes most likely caused by running
udevadm to prevent Nautilus popping up windows when the partition is
remounted. This can prevent the script from unmounting a partition
leading to errors.

Increase sleep time before unmounting, and add an option for users
to suppress popups.

Bump version to 2.5