++++++
**Features**
- Add option for specific XMI "type" field serialization. XMI uses a special
field to encode the type of the element. This field is almost always named:
``xsi:type``, but in some cases, ``xmi:type`` is used instead. To deal with such
cases, an option is now available: ``XMIOptions.OPTION_USE_XMI_TYPE``.
**Bugfixes**
- Add missing 'type' field for XMI href serialization. The 'xsi:type' field is
required when a crossreference is serialized. This field is used to check if
the resolved resource has the right type (not really, but it help). This
field is kinda optional at the moment for PyEcore, but required for Java-EMF,
otherwise the EMF will not be able to create the right proxy for the
crossreferenced resource.