- move Shadow configuration UI to libs
- removed useDropShadow and useOxygenShadow options, and replaced by activeShadow::enable and inactiveShadow::enable
- use kcfg for decoration configuration. The handling of exceptions requires dedicated readConfig and writeConfig methods, implemented in oxygenutils
- changed sizegrip combobox into a check box and rephrased for clarification
The flag has been made obsolete by the fact that window corners are not part of the shadow anymore.
Configuration::useOxygenShadows is now dealt with by setting the active flag directly.