XMI-Export: Wrong pins and doubled references (#105)

In this example the Action should receive Objects from 2 ObjectFlows through the Pin so the Pin should be an InputPin and the Pin should only have 2 references for the ObjectFlows. But its an OutputPin and there are 4 references. Both references are present twice.

<node xmi:id="ddip632056563629632085_934132207414983064" xmi:type="uml:Action">

<name>end</name>

<outgoing xmi:idref="ddip632056563629632085_298789131334321964" />

<output xmi:id="ddip632056563629632085_152977933787743660" xmi:type="uml:OutputPin">

<name>Pin2</name>

<incoming xmi:idref="ddip632056563629632085_613129828946694283" />

<incoming xmi:idref="ddip632056563629632085_996264875765520217" />

<incoming xmi:idref="ddip632056563629632085_613129828946694283" />

<incoming xmi:idref="ddip632056563629632085_996264875765520217" />

</output>

</node>