Cocoa: call SetFrontProcess on raise()

This will raise the window in front of windows from
other processes as well. Following Qt 4, only do this
for top-level windows.

Task-number: QTBUG-29087
Change-Id: Iae1b9c2928a627501112f97728198ed6dd614b2d
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qcocoawindow.mm

@@ -935,6 +935,9 @@ void QCocoaWindow::raise()
             [parentNSWindow addChildWindow:m_nsWindow ordered:NSWindowAbove];
         } else {
             [m_nsWindow orderFront: m_nsWindow];
+            ProcessSerialNumber psn;
+            GetCurrentProcess(&psn);
+            SetFrontProcessWithOptions(&psn, kSetFrontProcessFrontWindowOnly);
         }
     }
 }