Update CONVERGEIO reader to allow for per-boundary blocks.
I've attached a proposed update to vtkCONVERGECFDReader.cxx to allow for multi-block boundaries within the surface block. This will allow for behavior as seen in the screenshot. This does NOT coincide with any changes to the CONVERGE post h5 file, the format is still the same... it's just that the boundary behavior does not seem to have been in the original reader implementation. I haven't made a PR of this as I wanted to get opinion of kitware org. first.
