When trying to run the demo:

```
$ python demo_inpaint.py 
Inpainting plugin
----------------
Use mouse to paint the mask region white
Press OK to display the inpainted image.
Traceback (most recent call last):
  File "demo_inpaint.py", line 39, in <module>
    viewer = ImageViewer(image)
  File "/home/stefan/src/scikit-image/skimage/viewer/viewers/core.py", line 101, in __init__
    self.fig, self.ax = utils.figimage(image)
  File "/home/stefan/src/scikit-image/skimage/viewer/utils/core.py", line 201, in figimage
    fig, ax = new_plot(figsize=figsize, dpi=dpi)
  File "/home/stefan/src/scikit-image/skimage/viewer/utils/core.py", line 169, in new_plot
    canvas = new_canvas(**fig_kw)
  File "/home/stefan/src/scikit-image/skimage/viewer/utils/core.py", line 149, in new_canvas
    canvas = FigureCanvas(figure)
  File "/home/stefan/src/scikit-image/skimage/viewer/utils/core.py", line 132, in __init__
    QtGui.QSizePolicy.Expanding)
TypeError: arguments did not match any overloaded call:
  QWidget.setSizePolicy(QSizePolicy): argument 2 has unexpected type 'PySide.QtGui.QSizePolicy.Policy'
  QWidget.setSizePolicy(QSizePolicy.Policy, QSizePolicy.Policy): argument 2 has unexpected type 'PySide.QtGui.QSizePolicy.Policy'
```

Perhaps @tonysyu has seen this one before.