Implement transformation between the wxDisplay coordinate system and the Cocoa screen coordinate system. Use this to fix TLW initial positioning/sizing (including wxTopLevelWindow, wxFrame, and wxDialog) Use this to implement wxWindow::DoScreenToClient and DoClientToScreen Copyright 2007 Software 2000 Ltd. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@47995 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775