EnSight Binary uses 64bit longs so explicitly use those instead of long.

Using just long as the type will fail on window machine where long
size is 4 unlike Posix machines where it is 8. So we use the vtkTypeInt64
type which is always 8 bytes long.

Change-Id: Ib61d5e1860c411e44153904b497c525f392d2f32