FELIX-2169: Improve dev:show-tree performance and avoid NPE when no matching export is found

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@918963 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/karaf/features/core/pom.xml b/karaf/features/core/pom.xml
index aa3789a..58c19ea 100644
--- a/karaf/features/core/pom.xml
+++ b/karaf/features/core/pom.xml
@@ -55,6 +55,11 @@
         </dependency>
 
         <dependency>
+            <groupId>org.apache.felix.karaf</groupId>
+            <artifactId>org.apache.felix.karaf.commons</artifactId>
+        </dependency>
+
+        <dependency>
             <groupId>org.apache.felix.karaf.shell</groupId>
             <artifactId>org.apache.felix.karaf.shell.console</artifactId>
         </dependency>