New typemaps for wxString when compiling for Python 2.0 and beyond

New typemaps for wxString when compiling for Python 2.0 and beyond
that allow Unicode objects to be passed as well as String objects.  If
a Unicode object is passed PyString_AsStringAndSize is used to convert
it to a wxString using the default encoding.

Fixed the generic buttons so tool tips work for them.

Fixed a bug in the demo's tree control.

Added a listbox to the listbox demo that shows how to find items with
a patching prefix as keys are typed.

Added code to the wxListCtrl demo to show how to get text from a
column in report mode.

Added code to the toolbar demo to clear the long help from the status
bar after 2 seconds.

Added wxJoystick.

Fixed wxTimer so it can be used as described in the docs, either with
a Notify method in a subclass, or sending an event to a wxEvtHandler
object, (usually a window.)

Added wxNotifyEvent.Allow()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8764 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775