ENH: Update VTK - Add support for additional observer CallDataType

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vtkPythonCommand - Add support for additional call data types

This commit extends the mechanism added in 9366ca67 to support additional
data types.

Supported types now includes 'string0', 'vtkobject', 'int', 'long',
'double' and 'float'.

Also added convenience decorator 'set_call_data_type'

See inlined comments for more details.

The integration in VTK proper has been proposed here:
http://review.source.kitware.com/#/t/3966/
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git-svn-id: http://svn.slicer.org/Slicer4/trunk@22871 3bd1e089-480b-0410-8dfb-8563597acbee