Added missing view model.

de.hftstuttgart.buildingphysics.viewmodel/plugin.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <?eclipse version="3.4"?>
 <plugin>
-   <extension
-         point="org.eclipse.emf.ecp.view.model.provider.xmi.file">
-
-
-
-
-
-
-<file filePath="viewmodels/BuildingPhysicsCatalog.view"/>
-
+	<extension point="org.eclipse.emf.ecp.view.model.provider.xmi.file">
+		<file filePath="viewmodels/MaterialCategory.view"/>
+		<file filePath="viewmodels/BuildingPhysicsCatalog.view"/>
    </extension>
-
 </plugin>

de.hftstuttgart.buildingphysics.viewmodel/viewmodels/MaterialCategory.view

+<?xml version="1.0" encoding="UTF-8"?>
+<org.eclipse.emf.ecp.view.model:View xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ecore="http://www.eclipse.org/emf/2002/Ecore" xmlns:org.eclipse.emf.ecp.view.model="http://org/eclipse/emf/ecp/view/model/1180" xmlns:org.eclipse.emf.ecp.view.table.model="http://org/eclipse/emf/ecp/view/table/model/150" xmi:id="_ZY8TECUNEeux0PTSTJn6xg" name="MaterialCategory">
+  <rootEClass href="http://www.hftstuttgart.de/buildingphysics#//MaterialCategory"/>
+  <children xsi:type="org.eclipse.emf.ecp.view.table.model:TableControl" xmi:id="_cQS6sCUNEeux0PTSTJn6xg" detailEditing="WithPanel">
+    <domainModelReference xsi:type="org.eclipse.emf.ecp.view.table.model:TableDomainModelReference" xmi:id="_gQbIQCUNEeux0PTSTJn6xg">
+      <domainModelReference xsi:type="org.eclipse.emf.ecp.view.model:FeaturePathDomainModelReference" xmi:id="_gQbIQSUNEeux0PTSTJn6xg">
+        <domainModelEFeature xsi:type="ecore:EReference" href="http://www.hftstuttgart.de/buildingphysics#//MaterialCategory/material"/>
+      </domainModelReference>
+    </domainModelReference>
+  </children>
+  <ecorePaths>/de.hftstuttgart.buildingphysics/model/buildingphysics.ecore</ecorePaths>
+</org.eclipse.emf.ecp.view.model:View>