Cocoa: keep window focus and keep it exposed if going into borderless mode

Change-Id: If39ab50607b3faa09095a5e0418c89931884bffc
Revert earlier revert of qcocoamenu changes since qquickmenu has been patched

Change-Id: I0e0a0c75cba41db7f6cef9c6443337eadbc0b9e5
Only expose window when going in and out of frameless; otherwise QML tests can hang

Change-Id: Ib5d891f9a430a5a8cf7d870c4e9e0d12b05934cd
Fix build for QT_NO_BEARERMANAGEMENT
Merge branch 'st' into android-hidpi