Add missing attribute types (fix #96)

Author: Jelte Lagendijk

src/ChartJS/widgets/DoughnutChart/DoughnutChart.xml

@@ -116,6 +116,7 @@
 					<attributeType name="String"/>
 					<attributeType name="Integer"/>
 					<attributeType name="Float"/>
+                    <attributeType name="Decimal"/>
 				</attributeTypes>
 			</property>
             <!--<property key="sourceTrigger" type="attribute" entityProperty="sourceentity" allowNonPersistableEntities="true" required="false">

src/ChartJS/widgets/PieChart/PieChart.xml

@@ -119,6 +119,7 @@
 				<attributeType name="String"/>
                 <attributeType name="Integer"/>
                 <attributeType name="Float"/>
+                <attributeType name="Decimal"/>
             </attributeTypes>
         </property>
         <!--<property key="sourceTrigger" type="attribute" entityProperty="sourceentity" allowNonPersistableEntities="true" required="false">

src/ChartJS/widgets/StackedBarChart/StackedBarChart.xml

@@ -149,6 +149,7 @@
         <attributeType name="Float"/>
         <attributeType name="Integer"/>
         <attributeType name="Long"/>
+        <attributeType name="Decimal"/>
     </attributeTypes>
 </property>
 <property key="seriescolor" type="attribute" entityProperty="datasetentity" allowNonPersistableEntities="true" required="true">
@@ -208,6 +209,7 @@
         <attributeType name="Float"/>
         <attributeType name="Integer"/>
         <attributeType name="Long"/>
+        <attributeType name="Decimal"/>
     </attributeTypes>
 </property>
 <property key="seriesylabel" type="attribute" entityProperty="datapointentity" allowNonPersistableEntities="true" required="true">