Update for DE brightness button delta alignment

Update for 20.04

Add note about Ubuntu 18.04.2

Oops, we do need acpi

Tested on Ubuntu 18.04 & don't need acpi

Add that I've used it on Ubuntu upto 17.10

Update README to reflect test on Xenial

Restart acpid.service after installation

Update README.md

Minor adjustments to README

Note about uninstall nuking things

(Try to) fix some README formatting

Flesh out README

Also put uninstall.sh in installation directory

Initial commit (works for me)