This PR makes `dmenumount` script filter out all devices, which have childs. This way it won't suggest to mount your partitions which have LUKS or lvm setup on it.
If someone knows of a better way to do something, that'd be appreciated :)
* Remove misleading character escape.
Everything is in single quotes, so shell will escape it correctly
without backslashes. Fixes#440.
* Remove lsblk type restriction.
* Make it possible to cancel with ESC in dmenu.
Up to now if you pressed ESC to cancel the program would just continue
with incorrect data.
