This new filter use the Python annotation with a simple
front-end where the user only choose which scalar field
he wants to display. Time dependent value are automatically detected
and get updated when user change time.

The PythonAnnotationFilter now provides a new variable allowing the user to
access any block of a multi-block. 'inputMB[ blockIndex ]

Change-Id: Ib5ceb3c04bdb204f70a84ebc4afaed26859b39a6