Adjust filter for SCT nature from root property page (#1230)

* #1203 : remove filter for Sct nature from root property page (like root
preference page)

* #1203 : set same conditions as current only possible child page

plugins/org.yakindu.sct.ui/plugin.xml

@@ -37,10 +37,11 @@
             class="org.yakindu.sct.ui.preferences.SctRootPropertyPage"
             id="org.yakindu.sct.ui.properties.root"
             name="YAKINDU SCT">
-         <enabledWhen>
+        	<enabledWhen>
 	            <adapt type="org.eclipse.core.resources.IProject"/>
 			</enabledWhen>
-	     <filter name="projectNature" value="org.yakindu.sct.builder.SCTNature"/>
+	        <filter name="projectNature" value="org.eclipse.cdt.core.cnature"/>
+	        <filter name="projectNature" value="org.eclipse.xtext.ui.shared.xtextNature"/>
       </page>
    </extension>
 </plugin>