Add support for 'tool' category to ImageRegistryUtil

Change-Id: Ie2eff79f16c29d2e0a6134372ccccb64af07ae32
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/util/ImageRegistryUtil.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/util/ImageRegistryUtil.java
index db9e8d3..a289a0c 100644
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/util/ImageRegistryUtil.java
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/util/ImageRegistryUtil.java
@@ -80,6 +80,9 @@
 			case "obj": //$NON-NLS-1$
 				path= T_OVR + '/';
 				break;
+			case "tool": //$NON-NLS-1$
+				path= T_TOOL + '/';
+				break;
 			case "ovr": //$NON-NLS-1$
 				path= T_OVR + '/';
 				break;