NPanel dimensions & Dimmer: Panels have no margin they are full screen and prevent clicking on the bar until dismissed.

Margins are now included in the rectangle X,Y coordinates calculation

Might sound weird at first but it fixes a lot of inconsistencies/issues
we have had for a long time when a panel was open:
- can't close panel when clicking in a dead zone of the bar.
- hovering an icon on the bar used to make it look like you could
interact with it, but the click would just close the panel and not
actuall y do anything with bar .

I recommend turning back on dimming, as it is now way cooler. Changed
the default to true.

Commons/Settings.qml

@@ -328,7 +328,7 @@ Singleton {
       // general
       property JsonObject general: JsonObject {
         property string avatarImage: defaultAvatar
-        property bool dimDesktop: false
+        property bool dimDesktop: true
         property bool showScreenCorners: false
         property bool forceBlackScreenCorners: false
         property real radiusRatio: 1.0