HyperTreeList text search only works once

[cbeytas]

wxPython 4.0.3
Text typed into a HyperTreeList searches for a matching item, but it only works once.
The text (self._findPrefix) never gets reset by self._findTimer, which never gets started.

The search logic in the customtreectrl.py base class starts self._findTimer only if it evaluates False:

                if not self._findTimer:
                    self._findTimer = TreeFindTimer(self)

The __init__() method of HyperTreeList sets self._findTimer to a wx.Timer() instance so the timer is never started.

        self._findTimer = wx.Timer(self)

If this line is commented out or removed self._findTimer will get initialized to None by the customtreectrl init and everything works fine.