Can't save committed datatypes for non-numpy compatible types.

[jreadey]

Attempting to post a committed type that uses variable length strings fails. Andrew believes this is an h5py issue. I haven't tested it, but looks like this will fail for any of the "enhanced" datatypes in h5py (e.g. enums). I have a test case that is commented out for now: h5serv/test/integ/datatypetest.py - testPostVLenStringType. Issue is tracked here for h5py: https://github.com/h5py/h5py/issues/540.