* Removed CocoaInternalIdle()

* Removed CocoaInternalIdle()
* Removed methods that were called by wxTopLevelWindow notification handlers
* Removed now useless m_needMenuBar
* Added an Objective-C notification observer class
* Added methods to receive the notifications
* InstallMenuBarForWindow now takes a wxCocoaNSWindow
* Do not keep track of key/main window
* Keep track of window for which menu bar was installed (m_windowCurrent)
* SetMenuBar() will now install the main menu immediately

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@24430 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775