the new navigation bar shared by most assessment screens.
We need to verify this function may interfere with current implementation?
Add a new method OEXStyles ``-applyGlobalAppearance`` This will use the UIAppearance methods on UINavigationBar and UIBarButtonItem to set up the blue title bar+white text+icons. This should be called by OEXEnvironment setupEnvironment. It will probably need to set the tintColor on the main window as well.
Once that's done, we need to go through the app and verify that any existing UI looks reasonable. If not, take screenshots and document what looks wrong.