hdf5_msb

[svn-r18648] In H5T_get_native_type of H5Tnative.c, I changed the way that the offset, alignment, and 
size of nested compound type are calculated by using H5T_cmp_offset.  The old way had a bug 
in it (see bug #1850).

Tested on jam.  I tested the same change for 1.8 on amani, linew, and jam.