[sawfish] Drop the ugly hack around ?" and use ?\" instead
[sawfish] Add cycle-volume.sh script and binding for it

The script cycles between four volume levels on the Master channel: 30%,
40%, 50%, and 60%.
[sawfish] Do not assume home directory path and deduplicate some code

W-x and W-i binding are now dependent on existence of a file in
~/bin/libexec so first of all, do not assume what ~ is and use HOME
environmental valiable, and second of all, use commond function for
constructing the expression rather than duplicating the condition in
both lines.
[sawfish] When setting global bindis, pull code outside of a lambda

Instead of checking a condition inside of a lambda, the condition can
be checked outside and different lambdas created.  Similarly, (cdr spec)
can be precomputed outside of the lambda which has an added bonus of
one fewer cons being in the closure.