#12 PolicySet encoding not respecting XACML version

[Willem Salembier]

* When encoding an XACML 2.0 PolicySet, the namespace
uri isn't written to the stream.

PolicySet set = ...
ByteArrayOutputStream out = new ByteArrayOutputStream();
set.encode(out);

The PolicySet is correctly written into 2.0 format, but
when reading the xml stream the data is interpreted as
a 1.0 (=default) PolicySet.

To determine the xacml version; getNamespaceURI() is
evaluated --> AbstractPolicy (ln 263)

* There are other remarks in the code (eg constructor
AbstractPolicy) referring to the fact that metaData
handling isn't finished yet.

// FIXME: this needs to fill in the meta-data correctly
metaData = null;
(AbstractPolicy ln 180)