hdf5_ep

[svn-r8488] Purpose:
Bug fix.

Description:
Fixed handling of trivial data transform expressions (like 5/3 + 3) and some
data coversion fixes.  Also added more tests to dtransform.c

Solution:
Added some more checks in the H5Z_xform_reduce_tree function to see if perhaps
the transform expression is complicated and is a non-trivial reduction.
Added tests for data conversion to dtransform as well as tests for a trivial
data transform expression.

Platforms tested:
h5committest'ed, except used arabica instead of sol and didn't do on copper
b/c no logon there. Problem noted with mtime test...doesn't appear to be
related to anything having to do with data transforms.