Cocoa: Load the standard app menu.

Cocoa: Load the standard app menu.

It's now possible to quit and hide the app window
using the keyboard shortcuts.

The menu nib files are now stored in Qt resources,
written to QDir::temp at app startup and loaded
from there. This will simplify deployment compared
with Qt 4 where the nibs had to be copied into the
QtGui framework when deploying the app.

This change also moves the mac resources
(qt_menu.nib, cursors) from widgets to the cocoa
plugin.

Change-Id: If1d6fd353369ea4e89a9e35579906a2de7298fa2
Reviewed-on: http://codereview.qt.nokia.com/3314
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@nokia.com>