ENH: Made a correction to the RGB to XYZ color transfer (I made some missinterpretations about gamma correction and linearity in physical and perceptive).  This had several ramifications for CIELAB color spaces and transfer functions that rely on it.

a) Tracks all scalars present on the input data.
b) uses an Id channel array if specified.
c) Filter now outputs 2 datasets, the first is the trails, the second if the lead point on the trail. This is useful if you glyph the lead point and tube the trail, nice images can be generated.
d) much more stable in general
Many thanks to Ken Moreland for contributions to this class and to Benjamin Schindler of ETHZ for extensive testing and suggestions.

BUG: gcc4.1.2: QVTKPaintEngine.cxx:88: error: invalid use of undefined type ‘const struct QPainterPath’

ENH: added coverage: checking number of columns of the summary table as well (in case the Derive phase failed somehow).

       - SetupInputConnections was too close to SetInputConnections
       - PrepareInputConnections is similar to PrepareForRendering in that it give the representation an opportunity to make sure the inputs are all correctly in place, setup, etc.

ENH: Add a new 3D graph layout strategy from David Duke at University of Leeds (vtkSpanTreeLayoutStrategy)
ENH: Add updated tests using the 3D layout in the graph layout view
ENH: Add python examples using the graph layout view for the new strategy

view update the representation when it gets to it.

COMP: New Microsoft compilers have declared that using many STL algorithms on basic C pointers (a task that they were originally designed to handle) is 'unsafe'.  To protect me from myself, it now issues a warning any time I try to do something like copy one array to another.  There is no effective way around this without using special forms of the function that are unique to Microsoft's new compiler.  Essentially, I can no longer use these functions if I write portable code.  Thanks Microsoft

the name if none already exists.

ENH: First-pass changes to rendered representations to allow Qt-based labelling including unicode font.

manager would assume that all the new series were visible by default. That would
result in the legend showing all series even when some series were turned off in
ParaView after an explicit pipeline update. Fixed that.

BUG: Ensure that the signals from the options are connected correctly.

ENH: Add CanReadFile method to several readers to make it easier in ParaView (and potentially other applications) to choose the correct reader when the extension does not specify it correctly.

ENH: Functional simplifications to the Qt labeler to fit this in with the new rendered representation work.

changed since the vtkQtBarChart etc never have any checks if the value really
changed. This was resulting in series visibility updating incorrectly on
repeated toggling. Fixed that.