WIP: Add additional MetaDataObject explicit instantiation.

The MetaDataObject  of std::vector<std::vector<double> > > use by
Slicer's ResampleDTI module. This needed to be explicitly instantiated
and exported to enable dynamic_casts to correctly work.

Additionally other related types have been added that may be used in
other applications.

See http://review.source.kitware.com/#/c/15945/