With these changes, the full chain works on Arch Linux

Improved the scheme detection somewhat and added a check for adding '-s' if the scheme used is csi (chicken).

Added a logo script that will only be used if /usr/bin/logo.real exists. It's not perfect, but it will work also if the Arch Linux ucblogo package is updated in the future, and can then be removed.

Finally, the full chain works on Arch Linux!

```bash
#############
##  CHECK  ##
#############

diff QR.rb QR2.rb
[alexander@vzap quine-relay]$ echo $?
0
```