Less kludgy implementation of homePath()

Part of the KCM code assumes the users home dir is under "/home", which is not always the cause in linux - e.g OpenSUSE with AD Authentication uses a /home/DOMAIN hierarchy. Other systems use /opt. Not to mention windows etc.

The code adds a function homeRoot() which returns the parent directory of the uses home directory.

Built, installed. Adding paths to the exclude lists still recognise the home root.