[mac] bump version to 3.1.2
added @2x icons
[mac] remove linkage to Carbon
remove debug output
added more 2x icons
[mac] cmake support for osx bundle build now

 - remove os x bundle functionity from qmake
 - introduce some changes of osx bundle's directory layout
 - 1st attempt to migrate genapp.sh into cmake script
[cleanup] cleanup compiler warning
[mac] revert 3a186da since it is fixed in qt upstream

  - report is availabe at QTBUG
    https://bugreports.qt-project.org/browse/QTBUG-10899
  - eliminate compiler warning about deprecated usage of objc_class
[mac] fix margins of server-status-dialog