Adding a Resize option in ChartMatrix and Use it in ScatterPlot

vtkChartMatrix now features a SetSpecificResize allowing to move
the bottom left point of a single chart. This feature is used in
vtkScatterPlotMatrix to move the Big Chart plot a little on top right
in order to prevent overlap, using painter to compute axis bounding rect.
It also add a compare operator to vector in order to use it in the stl.