title: wxpython how to recreate grid?
body: <p>I want to recreate a grid. For example: old grid is 4x4, I want change it to 5x5.
  Here is my code:</p>
  
  <pre><code>import wx
  import wx.xrc
  import wx.grid
  
  class MyFrame2(wx.Frame):
      def __init__(self, parent):
          wx.Frame.__init__(self, parent, id=wx.ID_ANY, title=wx.EmptyString, pos=wx.DefaultPosition,
                            size=wx.Size(500, 300), style=wx.DEFAULT_FRAME_STYLE | wx.TAB_TRAVERSAL)
  
          bSizer4 = wx.BoxSizer(wx.VERTICAL)
          self.m_grid2 = wx.grid.Grid(self, wx.ID_ANY, wx.DefaultPosition, wx.DefaultSize, 0)
  
          # Grid
          self.m_grid2.CreateGrid(4, 4)
          bSizer4.Add(self.m_grid2, 0, wx.ALL, 5)
  
          self.m_button3 = wx.Button(self, wx.ID_ANY, u"MyButton", wx.DefaultPosition, wx.DefaultSize, 0)
          bSizer4.Add(self.m_button3, 0, wx.ALL, 5)
          self.m_button3.Bind(wx.EVT_BUTTON, self.OnClick)
  
          self.SetSizer(bSizer4)
          self.Layout()
  
      def OnClick(self, event):
          self.m_grid2.CreateGrid(5, 5)
          self.Layout()
  
  
  app = wx.App()
  frame = MyFrame2(None)
  frame.Show(True)
  app.MainLoop()
  </code></pre>
  
  <p>It raise an error when I run that:</p>
  
  <pre><code>File "C:\Python27\lib\site-packages\wx-3.0-msw\wx\grid.py", line 1221, in CreateGrid
      return _grid.Grid_CreateGrid(*args, **kwargs)
  wx._core.PyAssertionError: C++ assertion "!m_created" failed at ..\..\src\generic\grid.cpp(2325) in wxGrid::CreateGrid(): wxGrid::CreateGrid or wxGrid::SetTable called more than once
  </code></pre>
  
  <p>It seems I can't recreate this grid again. How can do this job?</p>