PV 5.5: Parallel EnSight reader cannot handle > 715M cells in 3ds mesh; fix attached

According to the EnSight Gold specification, the upper limit on the number of nodes and/or elements in a single part's mesh is 2 billion (# nodes and #elements are set by signed integers). Due to use of signed integers in vtkPEnSightGoldBinaryReader.cxx to compute offsets in the geometry file, in the best case this will fail catastrophically at (2^31 / 3) approx 715M cells when reading geometry mesh tuples or vector/tensor arrays.

I have attached diffs that alleviate this by computing offsets using long rather than int such that the reader complies with the spec's limit; I have checked that the new reader is capable of loading a dataset > 715M cells that immediately crashes in 5.5.2.

vtkPEnSightGoldBinaryReader.cxx.patch vtkPEnSightGoldBinaryReader.h.patch