Missing package diagrams from XMI

[ronaldtse]

In the ISO 19156 XMI, there are two "package diagrams" that are at the top-level:

They are not currently rendered.

We want to have them rendered prior to the rest of the package contents.

<diagram xmi:id="EAID_AEC50F38_A8C6_4a7d_820E_A329C08BB579">
  <model package="EAPK_4542A7F6_7BC7_4218_8D91_4B799164C14A" localID="39079" owner="EAPK_4542A7F6_7BC7_4218_8D91_4B799164C14A"/>
  <properties name="External package dependencies" type="Package"/>

[ronaldtse]

From @w00lf :

Currently we are rendering only child packages
we dont take into the account root package itself

These two diagrams belong to the root package.

[w00lf]

Was implemented in #45. @ronaldtse can we close it?