hdf5

[svn-r17678] Merge changes from 1.8
     - h5diff: h5diff treats two INFINITY values different. Fixed by checking (value==expect)
            before call ABS(...) at h5diff_array.c This will make that (INF==INF) is true
            (INF is treated as an number instead of NaN) (PC -- 2009/07/28)
     - h5diff: add option "--use-system-epsilon" to print difference if (|a-b| > EPSILON)
            Change default to use strict equality (PC -- 2009/09/12)