Fix media starting in wrong place
Minor fix for initial disabling of up and down arrow.
Fix media seek sliders from starting at wrong position
Interface unusable when run on XFce
Fix display to work with XFCE correctly
Attempt to load %General section, and just ignore those we don't know
Import %General, better error message, support 'players' section
Fix import of settings.

- QSettings exports the 'general' group as '%General' but appears in some circumstances (Linux?) to struggle to import this again. Try and compensate.

- Support the import of the 'players' section

- Change the setting group validation to skip those it doesn't know. Just test for an expected setting earlier instead. Also fix the error message.