-trigger the extended-panel to collapse completely before saving its position
    -save the prefs, if the extended-panel changed them previously (refs #382)
* extended.m: minor cleanups to make the stuff above possible (more cleanup needed, will follow later on)
* extended.nib & #.m: don't let the normvol-slider become zero, but use floats from 0.1 to 10.0 only