AGW on Phoenix: fix missing wx.EVT_MOUSE_CAPTURE_LOST handler in `LabelBook` and correctly place `AUIHandler` in the `persist` package.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxPython/Phoenix/trunk@73431 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775