Seek in file when skipping data elements.
Seek in file when skipping data elements.

Originally, the code was written on the assumption that PixelData
was the only large data element.  However, that is not always the
case.  This change allows the use of file seeking to skip over any
data element that is larger than the size of the file buffer.

dgobbi/vtk-dicom,dgobbi/vtk-dicom,dgobbi/vtk-dicom