macosx: Hide prefs window if application is inactive

Makes sure the prefs window does not stay on top and hides
all other applications if VLC is inactive.

(cherry picked from commit edf308064f80c9b6542f40f79f750b6206f7a643)
Signed-off-by: David Fuhrmann <dfuhrmann@videolan.org>

modules/gui/macosx/prefs.m

@@ -179,6 +179,7 @@ static VLCPrefs *_o_sharedMainInstance = nil;
 
     if (!OSX_SNOW_LEOPARD)
         [o_prefs_window setCollectionBehavior: NSWindowCollectionBehaviorFullScreenAuxiliary];
+    [o_prefs_window setHidesOnDeactivate:YES];
 
     [self initStrings];
     [o_prefs_view setBorderType: NSGrooveBorder];

modules/gui/macosx/simple_prefs.m

@@ -247,6 +247,7 @@ static VLCSimplePrefs *_o_sharedInstance = nil;
 
     if (!OSX_SNOW_LEOPARD)
         [o_sprefs_win setCollectionBehavior: NSWindowCollectionBehaviorFullScreenAuxiliary];
+    [o_sprefs_win setHidesOnDeactivate:YES];
 
     [o_hotkeys_listbox setTarget:self];
     [o_hotkeys_listbox setDoubleAction:@selector(hotkeyTableDoubleClick:)];