#16 Parser fooled by nameless NameValueType objects

[Gert Sclep]

When running
org.biomage.tools.xmlutils.ImportExportTest on a
MAGE-ML file extracted from ArrayExpress (identifier
E-CAGE-2), a NullPointerException was generated during
the output phase.

The cause was traced down to the existence of
NameValueType objects in the MAGE-ML where only the
type attribute had a non null value (and maybe more
precise: where the name had a null value).

OK, this is a clear error in the MAGE-ML file, but
shouldn't be Magestk be made a bit more robust in order
to survive these little input errors?

Gert